Since you are going through a chapter 13 you will not be able to qualify to buy a home but your girlfriend might. Since she may be the only one who may qualify that will be the only income that can be counted when checking to see if and how much she can qualify for. She will need to check with several lenders and see if she can get prequalified and if she can they will give her a good faith estimate, ie. how much she can borrow,etc. They should also guide you into how you can get your credit cleaned up and how long it may take.
Hope this helps!
Bob Parks Realty, Smryna TN