without knowing your full budget
I suggest you buy a used body. 50d is great, but has no video. They are cheap nowadays.
I 2nd the many suggestions of buying better lenses. Buying a used body frees up budget for lenses, cards, flashes, bags, etc, etc, etc. Did I mention that this is addictive?
Without knowing what your future plans are, I would suggest sticking with EF lenses in case you want to upgrade to full frame in the future.
Whatever you do, if you do consider buying an L lens ask yourself, "Can I afford this addiction?". I don't know a single person, who stopped at ONE L lens. I have 3 and going on 4.