The best thing would be to stick with the lenses you have and go for one of the 70-200mm L lenses to give you some extra reach. I would go for the 70-200mm f/2.8 L IS USM if you have the cash.


Then when you buy a ff body go for either 24-70 f/2.8L or the 24-105 f/4.0L, if you buy the 5D Mark II kit it comes with the 24-105 f/4.0L.


As always with a lens, buy the best you can afford, they can last for years and many body upgrades if you look after them.