We went trecking in Rwanda - everyone says its better there and it is just across the border of the Ugandan place. Permits are easier to get coz people are still paranoit because of the genocide - although Rwanda is very save now. Make sure you choose the biggest group (Susa) coz the chance to see a lot of them is bigger and there is more action.
PS.:This year I spent 6 Months in Tanzania (Arusha) and after the first day stopped taking my malaria tablets. They are in an excellent condition (we rented a house and they remained in a cubboard all the time - no exposure to sunlite and heat. I've got both, malarone and lariam. I would donate the money to the Shinda Basic School in Arusha where I worked for four months. Make an offer.