import wordpress users via csv including membership type and date

Hi
I hope someone can help me or give me some advice.
I am creating a membership website and am using the Membership plugin.
I have a list of current members that I need to import. I have been using import user by csv (http://wordpress.org/plugins/import-users-from-csv/). I am struggling with the following:

-current members have a membership number, i would like to use the user id in wordpress as the membership number. Can I import the members and assign them he relevant user id

-I would also like to import their membership subscription and expiry date, what are these field IDs for including in the csv file?

your help would be greatly appreciated.

Many thanks
Justin