cavy life questions

Question
As my christmas present this year, my mother finally allowed me to have a a guinea pig. :)
The more that I read about them, the more conflicting information I receive, so i'm looking for some clarity. First thing, what are some good examples of fresh fruit and veggies that I am supposed to be feeding him, and what amount should I be feeding? Second, is calcium good for my guinea pig? I bought him a calcium mineral chew, and he loves it, but I read that it may not be good for him, and does he need any other sort of mineral supplement? Third, do guinea pigs need exercise on a regular basis? and finally, sorry to take up so much of your time, but what temperature is appropriate? I will be living in the dorms and I can't promise a steady temperature in my room at all times, so if it gets too chilly, do you have any advice on how I should keep my piggy warm?
THANK YOU SO MUCH!

Answer
My cavies love apples, grapes and oranges among other things.  They also like carrots, green beans and celery.  The main thing you need to add to his diet is plenty of vitamin C.  I don't give mine calcium mineral chews.  Yes, you should allow your cavy plenty of exercise.  Don't worry about taking up my time.  :)  Thats what I am here for.  A temp that is comfortable to you is good for your cavy.  If you are cold, then they likely are cold to and etc.  You can purchase a warming light (not to big) if you are concerned about your cavy getting to cold.  Keep it only on one side of the cage so that your cavy can move if it gets to warm.