1. Do a google search on what GSM frequencies Kenya uses. If they use one or more of the ones a quadband phone has, then yes if should work.
2. My preference is ebay, but you can try factorydirect.ca, tigerdirect.ca, and I think puremobile.ca (or something) has been mentioned here before.
3. Did you try a google search on Kenya GSM? I found a couple of companies. Email a couple of them and ask them. Actually, do that first and make sure that the company that you go with uses one or more of the frequencies of the phone you're going to buy.