Membership site plugin

Hi folks

Can anyone help me find the right plugin?
I run a security business and have just bought a Studiopress “genesis” theme (driskill) which i want to use for my business site.

I need the site to allow members to register for free, so that they can enter (and then update at any time)their Keyholder contact details for 4 x names and telelephone numbers. We need to be able to access the data from the site, so that if there is a problem with their home alarm system reported to us, we can look up the data and contact their keyholders.

I will also need at some point, a payment processor, ideally one with affiliate tracking so that we can reward members for referral purchases from the site.

Is there a plugin out there which will do both jobs?

Thanks

Steve