Am I missing out by not running in 64-bit mode?
Lion is not meant to be used in 32bit mode. Also addressing more than 4GB ram with 32bit kernel is slower (it uses PAE).

If the only reason of using Lion in 32bit mode is the Cisco VPN client (yuck!) there is a way. Here is an article explaining how to use the native VPN client instead - it's for 10.6, but should work. It's a matter of configuration, not of software. And here is a forum post that pointed to thad solution.

About the Cisco VPN 3000 hardware - yes, it works with iOS and native OSX VPN client in IPSec mode, and it's a matter of software update and configuration. You should be running at least 4.7.2P according to the CISCO field notice. It's stated that it's not supported, but it works. Here is another success story. Make sure that you're using at least OSX 10.7.2.

ps. being tight on money is not always bad, It usually makes people more creative and makes them think and learn new things. Direct your network admin to serverfault, a place I'm sure he will get decent help.