As stated, there are three problem keys with that keyboard. Right shift will be the same size as left shift, so if you can find an extra shift key floating around from someone here, that would replace it perfectly.
Your windows key is smaller than standard, it's only one unit wide, as opposed to the standard 1.25 units. That's going to be harder to find a replacement for. Your best bet for that is to find a set of blank arrow keys or something with a matching colour. If you're looking for a temporary fix, the ./del key included in that set will be the correct size and profile.
The real problem is the spacebar. The spacebar mounts on that board are physically incompatible with pretty much every aftermarket spacebar out there. Only option I've heard for aftermarket spacebars is to take a knife and some epoxy and some donor keys and mod the spacebar you want to fit on the board.
All the other keys are completely 1:1 compatible. The biggest problem is the shift key, and I don't know of anyone off the top of my head who would have a spare one to sell. Let us know if you have more questions!
