Upgrade selected users to membership level with set expiration date

I have a list of members who either paid for or were gifted a subscription (either case, same subscription/membership/access level). How do I individually upgrade these users? Given the user_id, in Adminer (like PHPMyAdmin) -- since I can't hope to do it through the WP admin interface, as the Member Search does not work. Please help, I need to do this today... I need to grant these people the Gem/#1/full access level. Thanks.