I've just started collecting Lego, in particular the Marvel Universe stuff. I'm just wondering two things.

First. Can I order a replacement sticker sheet from Lego. I looked in their store and only found plastic pieces listed.

Second. As there are relatively few sets in the Lego Marvel range I'd like to get as many as I can. (It has only been on the market since 2012 and there are 22 sets released so far.) So is there a good place to get older sets, either brick and mortar or online? (I already know more reputable sites like BBTS won't sell outside their own country.)