Beware of anyone offering to "repair" your credit! The Federal Trade Commission issued a stern warning last year that such offers are scams. Find more from the FTC HERE. http://www.ftc.gov/bcp/edu/pubs/consumer/credit/cre13.shtm
The best way to buy a home is to have a decent credit history combined with sufficient Income and Assets for a home purchase.
The best way to have a decent credit history is to settle negative outstanding obligations and pay all your bills on time for at least two years.