Paul, you say..
IMHO it would be better if you did it the other way around and bought a new motor and a second hand wing. If you buy a good motor there is no reason that it should'nt do you for several years. On the other hand, if you get a nice calm wing to start on, which is a good idea, then you will probably grow out of it in a year or so.
Just my opinion, good luck,
Christian