Best answer by Bradley_Boost
I've changed your topic slightly so it can be easily found by other users who maybe asking the same questions or looking for the same answer!
Ultimately, yes you can move any credit in your Winter Wallet across to your main balance to top up.
You won't be able to do this yourself though, you'll need to reach out to one of the Boost team to get this moved over!
You can pop the team a message via their Facebook page here, or you can pop the team an email at firstname.lastname@example.org.