A lender would likely approve you up to $244,747
On $73,000 of gross income with $550 of existing monthly debt, the 28/36 rule supports about $1,640 a month toward housing. With $42,000 down at 6.65%, that reaches roughly $244,747 — a $202,747 loan at 17.2% down. Your resulting debt-to-income ratio would be 36%, and you are currently limited by the total debt.