From standard point, you need at least 400mm lens. Also the lens should have at least f4 aperture, and better has the Image Stabilization, plus you need the monopod too. For your budget you can get the best one, try this and I think someone else will find other good deal for you too.
http
/www.amazon.co.uk/Canon-70-300mm-4-0-5-6-USM-Lens/dp/B000B84KB6/ref=sr_1_7?s=photo&ie=UTF8&qid=1368742847&sr=1-7