Ooohh we love spending other people's money here!
I'm sure the rest will be along soon with their suggestions. Which if the two lenses do you find you're using more? I'd guess that it's the tele?
Perhaps something like the 70-200mm f2.8L is anoption, you can probably get one from TM for less than $1500
If you want a standard zoom, for similar money you can get a 24-70mm f2.8L
With the change, you can grab the Tameon 17-50mm f2.8 which is about $4-600
Hope that helps!