Should I haggle my APR with my credit union?

I'm applying for an auto loan. Both hubby and I have credit scores well over 730. Our only debt is one credit card and the debt on that is below 2/3 of the card's maximum. We pay it, and all of our bills, on time, etc... we're outstanding borrowers. I make $1400 a month before taxes, and hubby makes about $1500 per month. Considering all this what APR could we haggle for in today's economy? I'm new at my job and have only 3 pay stubs so far. Your help is appreciated :D Also, if you would have any advice as to how much my lender would be willing to loan me I would appreciate it. We have a lot of financial collateral as we have a savings account with $2,000 that we pay into and let grow (it's our emergency fund).