Q. I fell behind on my mortgage. My house in Bucks County, Pa., went into foreclosure and was sold at auction. The mortgage company purchased it. My lawyer stated that the mortgage company made some mistake during the foreclosure and he was going to try and reverse the sale and allow me to keep my old mortgage, but we had to move fast because you only have certain amount time before the title is transferred. If that doesn't work my lawyer said the mortgage company is willing to sell my house back to me but I would have to finance the purchase with a new mortgage. Of course, my credit is awful now. What can I do?

A.According to Marc Kranston, a real estate attorney in Allentown, you can petition the court in your county to set aside the sale of your home if there are legal grounds for doing so. The two most frequently used and successful challenges are:

• An irregularity in the foreclosure procedure like failing to provide you with adequate notice.
• Gross inadequacy of price, which means the house sold for far less than its fair value.

Fraud in the lending process or sale would also provide a basis to stop the seizure. A common example is when loan officers secretly inflate a buyer's income or assets to qualify for a bigger mortgage that the buyer can hope to repay.

But that's harder to prove and isn't used nearly as often in these petitions.

If you're going to challenge the sale, you must do so before the county sheriff delivers the deed to the purchaser (the mortgage company, in your case). How long it takes the sheriff to deliver the deed varies by county and depends on the sheriff's office procedures and how many foreclosures the sheriff's office deals with. The good news is that the minimum time to deliver the deed is 45 days after the auction.

Should you be successful and the court rules in your favor, the house is relisted for sale. Under Pennsylvania law, the relisting gives you the opportunity to keep your existing mortgage by paying the mortgage company what you owe in missed payments, along with any sale-related costs the mortgage company incurred and reasonable attorney's fees.

If you don't have the money to pay the missed payments and additional costs, you can file for Chapter 13 bankruptcy, which lets you pay the missing payments and costs over five years. After you've completed the five-year payment plan, your mortgage is reinstated and you pay the rest off as you would normally.

What we don't know is what kind of mortgage you have and whether there's any hope you could keep up with the payments even if you catch up and it's reinstated. You'll need to take a good hard look at your mortgage and your finances, to determine that.

Just make sure you don't wage a long and potentially costly legal battle to keep a mortgage that you can't afford even if you win.

Re-buying your home from the bank will be difficult. It's hard for almost anyone with bad credit to get a mortgage right now and a recent foreclosure will not help.

The first thing you need to do is go to Equifax and buy Score Power, which will provide a credit report and FICO credit score for $15.95. The FICO score is the one created by Fair Isaac Corp. and is the one used by virtually every lender. The other major credit agencies, TransUnion and Experian, have stopped selling FICO scores and are now selling the Vantage PLUS score, which uses a different scoring formula than FICO, is not comparable to FICO, and is not widely used by lenders. Don't pay for that.

If your credit score is below 620, and we suspect it will be, you'll be considered a subprime credit risk. Because so many subprime borrowers are in trouble right now, it's very hard to find anyone willing to make new subprime loans.

But the best place to look is a lead aggregator like bankrateselect.com or nextag.com. Those sites will ask for some basic financial information and share it with dozens of potential lenders -- and they claim they still have some ready to work with subprime borrowers. If that's the case, it could take anywhere from a few minutes to a couple of days to hear back from them.

If you pursue a new loan to re-buy your home, just make sure you don't get pulled into a dangerous, adjustable-rate mortgage that could land you back in trouble a few years from now. At this point, you need a safe, predictable 30- or 40-year fixed-rate loan. Just be prepared to pay a high interest rate of at least 9% or 10% on any subprime mortgage.

Barbara Nichols, the owner of Nichols Real Estate and General Contracting of Beverly Hills, Calif., and author of "The No-Lawsuit Guide to Real Estate Transactions," has another suggestion: Ask a relative or good friend to co-sign the new mortgage with you.

Your lawyer could draft an agreement that would protect your relative or friend's financial interests if you failed to keep up the payments and they were forced to assume responsibility for the mortgage. But if your co-signers have good credit, you would have no problem finding a mortgage at reasonable rates.