buy a series two front halfcut ( without motor if you can find one or sell motor) make sure you get all panels, bonnet and bonnet release and rio etc. in reasonable to good condition ( less fixit work before painting)
EDIT: don't forget the headlights..
swap the front guards, bar, bonnet etc. onto you car and then get it all sprayed or have it sprayed prior to fitting its up to you.
then hey presto series two conversion
you could go the whole hog and replace your dash aswell to get the dual airbags and all the seats and interior trim if you wanted but then you should probably just buy a series two IMO.
Corey.