Hi,
Unless you are dead set on spending money I would advise taking time to set up your existing 1/2 mildlot scope and practice getting your head/eye position the same for prone, kneeling and standing shots.
Do you shoot at Bisley? If you really want a new scope and shoot at Bisley ask to look through other members scopes to see what you like before committing cashola!
Cheers Rich.