to be honest i'd just bin the recovery discs and start from fresh. The backup discs you created will not restore your installed programs and settings anyway. You don't need any of the software from acer anyway, it's all just junk. Next time make sure you make an image of you disk using a program like norton ghost or casperXP before you give your disk to anyone to fix or replace. In fact i would go so far as to say NEVER hand back your PC with ANY data on it, not to anyone, ever. Back up you email, web browser favorites, and save a copy of any installed software and the keys to activate them and then your covered. If you are required to send you computer back make sure that you fully format the HD before it goes anywhere, preferably using a professional software program that writes over any data 100's of times thus enabling it impossible to recover.
If you still want to try the recovery process from you backup hard drive copy, then it won't matter how big the drive is as long as the amount of data your trying to restore is more than the available space on the new drive. It should let you re-partition the drive when your restoring it.
Good luck. Come back if you have any problems and i'll try my best to help.