Suggestion on building a Saas web app

[zonedp]

I am wanting to have a SAAS site built but I am not sure what language(s) should be used.

The script I want to charge for is mostly PHP and MySQL based but how would someone wrap this with a CMS to manage members?

Basic functions of the system:

1. Create a user account
2. Setup the script in the user account
3. Abilty to charge for a set number of projects in the member plan
4. Multilevel membership plans
5. Reoccurring billing

I would really appreciate any suggestions whether it is a pre-built CMS or something I would need to have custom programmed.

Also if there is a better section for this question please lmk

[zonedp]

Anyone? Just looking for some direction

[PCSpectra]

PHP for the win....Drupal would get you half way there.