well everybody has already posted most of the necessary places you can visit here. just to add about where to eat
since you can eat, chicken and beef, then you will not have a problem with food. just go get a "karagi" or "gyudon" or go to a yakiniku shop and you will be fine, even the packed lunch "bento" is ok.
speaking of yakiniku, in between Ueno and Akihabara there is a yakiniku store called "Carne Station", its an eat/drink all you can restaurant for 1 hour , i think its about 1500yen per person. its located under the railway so you wont missed it. It's at the end of akihabara before entering ame yuko in Ueno.
Try ame yuko also its a shopping street in Ueno, lots of interesting shops and food to try there. oh yeah its also a wet market beside it that sells fishes, so it might get a bit stinky
