Hi! I currently own a Canon EOS 1000D (with EF-S 18-55MM IS) and a EF 75-300 mm f/4-5.6 IIIUSM Ultrasonic lens. Should I:

1)Trade in camera body with 75-300 mm lens and upgrade to a 2nd hand prosumer or professional DSLR.
2)Trade in camera body without 75-300 mm lens and upgrade to 2nd hand prosumer or professional DSLR.
3)or any other suggestions?(:

Thanks! (: