am going to australia for 2 years to study and that means that i can't share lenses with my fren anymore. i bought my canon rebel 2000 with the basic 28-90 lens and i figure that i should buy a zoom lens. can anyone recommend me some? i dun mind anything really but preferably to at least 200mm? and it would be perfect if i could get it for less than $300. please help! oh and where could i get it too?