First you’ll want to go to each of the extensions providers and check to make sure that the extensions you were using are compatible with 1.7. Often they will have newer/different versions of their extensions that work for 1.7 vs. 1.4.
If you’ve purchased the extensions via their websites, you should be able to sign in with the account you used to purchase them and download them again from the Your Account page. If you had your developer purchase them on your behalf, contact your developer and have them re-download the extensions for you.
Once you have the new download packages, just install them like you normally would.