How do you switch regions?

Im almost level 11 and get no xp for killing things in the first region how can i switch to another one? oh and one other question i cant figure out is how can i leave my guild?

Take quests, do missions, and follow the story line. That will lead you to new areas with higher-level enemies. It would help if we knew what campaign you were playing, since each one works a bit differently.

That. and for the guild, press "G" and find your name. see that little icon of a person? click that and then an option will pop up (Leave My Guild) press that.
NP.

If you started in the first campaign (Prophesies) you are probably in the starting area called Pre-Searing. To leave Pre just go to Ascalon city and talk to the quest giver whose quest has a lot of red text and says something like "if you leave now you can't come back.... make sure you have all your business settled before accepting...etc."

If you started in Factions or Nightfall, just follow the quest lines and missions.