How do I download my sims purchase on my iPad?

If these are for a computer, they will not work on the iPad. Only apps and content from the App Store or iTunes can be downloaded and installed on the iPad.

If they are for the iPad, you have to sync then from iTunes or just download them onto the iPadfrom the app store via the purchase tab in the app store.

I've never made an in app purchase for any app on any device but where do you see the purchases on the Mac? Do you see them in your iTunes library somewhere?

I assume that you have to sync them to the iPad, but that's just a guess. Did you look in the game itself to see if the purchases transferred to the app?

There is one thing in your post that I have to question. You said you bought these in the App Store. Not the Mac App Store I hope, do you mean in iTunes on your Mac?

Yes I know what they are and that's what I was afraid of. If the purchases are not showing somewhere in iTunes when your iPad is connected to the computer, I'm not sure how to get them to the iPad.

Connect the iPad to your computer, launch iTunes, click on your iPad name on the left side. Click on the apps tab.

Do these Purchases appear anywhere in there?

I'm not sure that this will help. I see nothing that talks about moving the purchase into iTunes so that you can sync them.

http://support.apple.com/kb/ht4009#