if you want it sooner, i would downgrade the HDD and RAM, keep the GPU as it is.
heres an offer on Win7+500GB
http://www.overclockers.co.uk/showproduct.php?prodid=SW-000-OP&groupid=33&catid=1963&subcat=
heres an offer on Win7+500GB
http://www.overclockers.co.uk/showproduct.php?prodid=SW-000-OP&groupid=33&catid=1963&subcat=