The Chicago Real Estate Daily says come October, the maximum amount of a government-backed loan in the six-county Chicago area will drop $45,000 to $365,700.  Currently a home buyer can put down 3.5 percent on the purchase of a Federal Housing Administration (FHA) approved home costing $424,870, and finance the remainder.  The new limit will drop that number to $378,964.  Analysts say this will adversely affect the market, causing home buyers to consider less expensive homes and forcing the prices down on existing homes for sale, further stalling a potential housing recovery in the Chicago area.  The National Association of Home Builders (NAHB) says of the two million owner-occupied homes, nearly 28 percent will be affected by this ruling set to take effect Oct. 1.