If you have a good local bike shop or a decent sporting goods store close by you will have better luck at getting a bike rack that will last you awhile. I like the Yakima suggestion, they make good products. Allen bike racks are also good products and not so expensive. I have a Rhode Gear trunk mounted rack and like it.

If Walmart is your only option you should be able to make the rack work in the short term --- or maybe you can borrow one from a buddy? Or rent one?

Good luck!

-traveller