A lender would likely approve you up to $274,905
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 $55,000 down at 6.65%, that reaches roughly $274,905 — a $219,905 loan at 20% down. Your resulting debt-to-income ratio would be 36%, and you are currently limited by the total debt.