Any question answered...

I need new some new forks...
You need 1", not 1 1/8".
Stack height of whatever headset you're going to use (if you're going from threadless to threaded you'll need a new one*) plus length of your head tube will tell you the minimum steerer length you'l need, with the threaded portion extending below that minimum.
If you find some forks with a longer steerer, they can be cut down, and it's usually possible to get more thread added by a decent LBS or framebuilder.

*unless your current one can be converted *a la *Chris King...