We have a 2009 Pontiac G6 GT with 76700 miles on it and we are looking to get a new SUV.?

We still owe about 13,000 dollars on our Pontiac and if we trade it in we will get about $7500. We also have a 2001 Dodge Ram 1500 that we still owe about $1000 on. This has about 100,000 miles on it. My husband has a credit score of 580 and we want to keep our monthly payments at $400. We have no down payment. The SUV we want is the 2011 Chevrolet Equinox. We have already been into a dealership and they denied us. My question is how do we get into this new car? We are in the military and are going to be moving in January. We also have a baby coming this august and this is the main reason for us trying to get this SUV. We have a big dog that goes everywhere with us and something like this is just more family friendly for us. Can anybody give us some advice? Thanks :)