Where could I get Scuba Gear?

I recently got into scuba diving. All I've done so far is you know the mask, fins, snorkle combo and dive to the bottom of my buddies pool and come up without surfacing. I don't know exactly what I need. I was just wondering where I could get a Good mask, and fins and possibly a tank if their are small ones that arent to luggish. You know one I could use in a swimming pool. Also, is it possible to stop my ears from hurting when I get to deep. When I get to the bottom of the pool my ears start hurting a little bit. Nothing bad just alittle. I was wondering if I could stop that. Thanks for any help.