You have a bike. Yeah, it's not great, but that's ok for now. Bikes are not that complex. Go tinker with the bike you have and learn how it works. Other than setting up the frame you don't need a lot of specialized tools....yeah, they help, but you can get by with some basics. Decent set of metric allen wrenches, couple screwdrivers, a set of narrowish metric wrenches, and you can go tinker with it to your heart's content. Read the Park tool website for some good info on what and how to make adjustments.

With an hour of reading and tweaking, you can get your bike shifting smoothly. Then ride it until you figure out what you want next. By the time you really know what you want, you'll have a free education courtesy of fiddling with your existing bike.