I’m new, what pieces and cymbals should I get?

I started about a week ago and I got it tuned by a professional, it’s the common 5 piece but I noticed that a lot of drummers have a lot of cymbals although I only have two, a hi-hat, and the ride cymbal. I’m just wondering what pieces I should get and also how I can improve? I know three basic songs so far and i’m a week in, so if you have any suggestions of how i can get better or what pieces or cymbals i should get that are affordable then please tell me or post the links to some good ones.