Musings from a small IPP

Does anyone understand the mess of side effects called Joomla enough to write code?

I need to quickly replicate some functionality from a hacked Mambo system into Joomla.
Mambo code exists and is available.

Requirement:

1. Check in external table for criteria which would allow account creation, and create a link table entry if successful, in addition to creating the account
2. Link searches of the external table into the Joomla search, presenting (some of) the data — varying by whether other user / self / administrator (see also 4)
3. link to an external program to take subscription renewal, or print a membership card (program exists)
4. Allow users to edit(some of) their entries in the external tables and notify Administrator of changes made by email
5. Nice to have : Chain to renew subscription if logging in after subscription has expired.

This is a very short term job, no on-site requirement. If interested please contact us