I need to get back into the mages guild cuz I've been kicked out. They want me to get 20 deadra hearts and 20 vampire dust. I can get the dust but I already beat the main quest which shut down the oblivion gates. So I cant find any deadra...=( What do I do???

some elvin temples will have daedra type monsters inside the Xivalixz or whatever drops them and I come across that guy all the time in temples, at least at my level.

Lots of the Xivilai at forts as well. They'll respawn too if you leave the area.

You got a slightly different reinstatement quest - wish I had that! I have to get 20 Dragon's Breath (or something like that) and 20 redsomething or other flowers and don't want to traipse around all over to find them. There are only a limited number at alchemist's shops. I did this as arch-mage too, so it's pretty funny. Oh well. I'll get back in eventually.