You may approach this by offering $160k, and have the seller make all repairs prior to closing (which isn't too likely)
or you can buy the home with FHA's 203k rehab program, which would allow you to finance the purchase price + the cost of improvements, minus a 3.5% down payment on the total figure. Very detailed information about the program can be found at
http://www.hud.gov/offices/hsg/sfh/203k/203kabou.cfm but if you have more questions about it feel free to post them in your thread here. The seller can pay your closing costs on a 203k loan as well (up to 6% of the sales price), so if you negotiate the contract that way you would just need to bring in the 3.5% down payment at closing.
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