As mentioned numerous times, don't attempt to finance things you cant afford or don't need. I assume this is your fist time attempting to own rims, because if you actually knew what a pain in the *** they are you would say forget it.
Take into consideration that when you do get rims you are probably going to get low profile tires which can cost more than the rims (unless you get a package deal), you have to drive more cautious than before because once you hit a decent sized pothole or object they will bend/warp and you are setting yourself up for theft as well. Just wait until you have the money and go that route, financing is how companies make their money by giving you an extreme interest rates and they end up raping you when all is said and done.