Question about changing from Membership to Membership 2

Greetings! Everyone was so kind to help us get Membership rolling for our website ... We were looking to upgrade this to Membership2 but realized the payment gateway option for 2CO is not longer available in Membership2. Is there a way to tag/connect to that from Membership2 and/or is there a spot we can redownload the original Membership? Thanks so much for your help! All the Best, Kerry Fink