70-200F4L and a monopod

that will put you over $600 slightly, BUT you will LOVE it.

the 70-300 is a variable aperture lens, the front element extends while focusing(I think), no UD glass(which L lenses have), no lens hood included, no soft case either, no full time manual focus....

70-200F4L.... focuses 1 foot closer, lens hood/ soft case included, internal zoom/focus , L glass, same weight relatively, tripod foot AVAILABLE(though it's $120), faster focus motor, focus limiter(I think)