Total debt divided by total income .
You will have 3 figures: Your's, her's, and combined. Work on adjusting all 3.
The 45% is to include your mortgage, CCs, and all loans. Any loan with less than 10 months left on it is usually not (and shouldn't be) calculated into this. With 10 months left it is 'short-term debt' - a mortgage lender is more concerned with the longer term.
the 15K would give you a -3% downpayment at your min price but no money for closing costs (not too much of a problem in this type of market)
A $485,000, 30 year note at 6.5% will cost about $3065 per month not including insurance, PMI and taxes.
HTH