is it not under warranty? you should be able to contact acer and ask them to send you the parts you require... the tough part is getting hold of the part number for the touchpad. the number you're looking for is in the format of XX.XXXXX.XXX
if you phone them up they should be able to get the new parts for you if you tell them what it is, you dont necessarily need the part number.
if its out of warranty and you want them to fit it then you will have to pay labour costs; i was told today that its something like £60