on-line membership database

I founded the National Association of Sessional GPs [login to view URL] (formerly NANP) some 8 years ago – we’re a voluntary organisation supporting General Practitioners who work part-time. We currently have 1,400 members, and run our membership database with ‘home-made’ Microsoft Access. We’d now like to transfer our database to an on-line version that allows our members to do most of the work, and in particular generates username/passwords for access to our website. Here is a list of the things we want out of our database: • Preferably, browser based i.e. internet explorer • Our current database is Access 2003 - so to reduce costs, I assume that if our new database is based on this it would cut costs? • We - back here at base - would like to have to do as little as possible in terms of maintaining the database, and our members have to all the dirty work - entering their details, credit-card payments etc. • Ideally, they'll be able to set up the credit-card equivalent of a direct-debit? • We WILL need an option for members to pay by cheque (there's a lot of luddites out there - I expect this would mean that rather than each individual adding/purchasing their membership, they post it to us and we add it on-line on their behalf). • If it’ll help I can send you our current database which will give you an idea of how we use it. • 
we reckon that reminders are best sent via snail-mail, perhaps followed up within 48 hours with an identical email. • Currently our members can receive all their membership benefits free of charge simply by logging on to our website at [login to view URL], so we'd like to password-protect the site and let only members log in - can you do this? In effect, the password is the product they're purchasing (plus the odd Newsletter that we snail-mail out to them). • I'd want the password to be available for them instantly to use, to be customisable (so that it can be the same as their usual passwords) and easy to request when they inevitably forget it (usual mother's maiden name prompts I guess). This password would then grant them access to the main bulk of our website (in effect, our product). • we'd need help/advice password-protecting our website - i run the website using FrontPage and all my programming skills come from having read FrontPage for Dummies. Do you think consensus could offer what we need, and if so for what cost?