You should be able to use all the things you have updated for the v1 PowerStore. Just setup a site for the new v2 PowerStore, then open the globals file and copy the values from your v1 store.
Check the connection file to ensure that you have the same values as your v1. Once you have confirmed this is all in place and working you can backup any of the css for the new v2 store and use your css from the v1. Updating the css will probably the trickiest part since the v2 does not exactly match the look and feel of v1. So long as you have the css for v2 backed up you should be able to get it working.