Just to get you started thinking about gear (aside from the helpful list Oregon Mouse pointed out to you elsewhere in this thread).
The key pieces of gear, imo, are: sleeping bag, footwear, and pack. The footwear and pack are all about how well they fit the shape of your foot and your body, so it is hard for a bunch of strangers to tell you what is going to work best for you. You'll be wearing both the footwear and the pack for long hours so good fit is critical. Chafing, hot spots or sore hips are bad signs. Ten minutes isn't long enough to evaluate fit in a store.
Other primary considerations for a pack: it needs to be big enough to fit everything you need to carry, both food and gear, but not any bigger. In Yosemite that also includes a bear canister for your food, which is somewhat bulky. It is good advice to leave buying the pack for later and get your gear together first.
In Yosemite, you'll be at very high elevation and it can get cold at night, even in July. Very cold for a Floridian. Your bag should probably be rated at 20 degrees if it is a good-quality down bag from a high-end manufacturer like Western Mountaineering. If you can't afford a high end bag, I'd buy something rated for 15 degrees, because lower quality bags are alsways over-optimistically rated.
If you spend a ton of money on any piece of gear, make it your sleeping bag, not some nifty toy. A GPS can't keep you from freezing at night.