What bills are used to determine the DTI? I have a car payment and one credit card That shows up on my credit report. Then I have the usual rent, utilities and such.
Basically anything that you're obligated to pay, so things like utilities don't count because you could technically cancel them at any time. They just go by whatever minimum payments appear on your credit report, but you're supposed to also disclose any other obligations you have tha don't appear (like payment arragements for a judgment or tax lien). They won't count your current rent, but they will count whatever the new mortgage payment (including principle, interest, taxes, insurance) will be.
Front end ratio is the PITI (principle, interest, taxes, insurance). The guideline is usually 31% of your monthly income, while back end (PITI + all other monthly debts) is usually 43%.