You can still use XP for a good while to come. XP isn't going to stop working, they just aren't going to be giving out security patches anymore. As long as your up to current, have a decent Anti-virus check, and aren't going to any unusual sites, I would say XP still has another year or two left. Of Course thats just my opinion.
As for another OS, what are your hardware specs? Have you ever installed a OS before?
PS. Might want to check out this article. Does a good job breaking down the options if upgrading/changing OS is the way your going.
