Converting to Drupal

About a year ago we started building a social networking site from scratch using LAMP, HTML, and Perl. Although we have completed first revision of some basic modules but we have a long way to go. Now we are evaluating integration of (or switching to) Drupal or Joomla (or another that you may recommend). We have somewhat limited programming and administration resources and expertise. We have looked at CMSmatrix site to compare the two. Your comments and guidance on the following will help a great deal:

http://www.oxfordms.net

and would custom pages like:

http://www.oxfordms.net/concern.php

stay the same?

Thanks,
Dukester

Hello, how does one create a set of documents in a single page such as this:

http://www.city.pittsburgh.pa.us/main/html/city_documents.html

Hi, we are considering converting our site to drupal, drupal is looking good so far but there is one function that we need on the website for staff that I have been unable to find so far by searching through the modules.

How trivial would it be to convert from a Drupal theme to CSS/HTML? Thanks.

I installed drupal for 1st time (new user). Many of the mods I need only work with Drupal 5.9 or earlier. Should I install an older version of Drupal? I don't want to wait and hope all these mods will be updated.
Thanks for any input!