Check out our Marvel Mega-Recommendations Thread to get recommendations from our members on comics that may interest you. Your thread has been merged into that one. It is a good place to ask others for good books to read and to look through for past recommendations as well since you are just getting started.
And as far as where you can buy comics, there were good answers given to you for online dealers. Any major search engine will offer even more if those aren't enough. Ebay is good too. Use CBR's comic shop locator to find a local store near you. It is great if you can visit a comic shop as they will generally have a wide selection of current and older books as well as customers that share an interest.
Welcome to CBR Forums and the world of comics. You picked a great time to get involved.
Also, your interests seem to be in the X-Men line. Check out our X-Forum which focuses on Marvel's Mutant books and topics.