If your heart's really set on a Tak, then I'd keep saving. For me I found that my SW Esprit 100 is more than enough. It strikes a balance between price, aperture and portability with comparable performance to a Tak (
Comparison). I guess If i were to upgrade I'd go with something like a Tele Vue-NP101 for a flat visual field or maybe something a little bigger. Have a look around on reviews and astro-bin maybe something like a SW 120ED could suit you has a 765mm focal length with the reducer, I'd doubt you would have trouble selling it.