Erin, like suggested, until you have established a proper nitrogen cycle in your tank, you've got to do water changes to bring the ammonia level down. It's not ideal to get it from a LFS, but can your store give you some well established bio media from one of their filters? Take it home in a fish-bag with water and place it in your filter. If you know someone with a healthy, established tank, it would be better to get it from them. This will supercharge your nitrogen cycle and start the process of converting ammonia to nitrites to nitrates.
If you were near me, I'd give you a sponge bubbler, or a sponge or bio media out of one of my aquaclear filters.