Should I use beowulf?

Hello, hope somebody is out there.

I've got an application that ties together several different other 
applications.

It's written in python, managed via apache, queries MySQL, and creates 
text files that are processed by asterisk, which launches a VOIP (SIP) 
session.

It's solid, works well, but when I try to get to the desired volume of 
calls, the CPU Load on my Quad 3.6Ghz server spikes to 22.0, so I'm 
stuck with about half of what I'm trying to get done, with a load of 3 - 5.

The main culprit here is Asterisk, which uses Shared Memory, so I know I 
won't get any benefit for that particular program out of beowulf. The 
python part is extremely lightweight, and aside from the main call-file 
generating daemon, a slew of cgi and helper programs kick in from time 
to time to do database updates.

I know that I'm going to invest in a couple more dual core processors, 
which would bring my total count up to 8 cores, or 24ghz, on the server.

If I were to make this server the beowulf master and plug in my 12 P4 
3ghz machines into the cluster, do you think it would migrate the other 
programs to the nodes, freeing up the server's processor to focus on the 
asterisk tasks?

Or would I be better served moving the sql, apache, etc to another 
server, performing my db lookups across a dedicated network?

And  a side question that I probably already know the answer to, can I 
have 32bit nodes with a 64bit master?