Need advice on how to configure

I am BRAND NEW to MikroTik… but I like what I have seen so far!

Here is what I have now…
RB750GL
Port 1: LAN (No DHCP)
Port 2: WAN1
Port 3: WAN2

I have used the scripts that I found to load balance between 2 DSL connections (http://aacable.wordpress.com/2011/07/27/mikrotik-dual-wan-load-balancing-using-pcc-method-complete-script-by-zaib/)

I have figured out how to enable DHCP on the LAN… but I DO NOT WANT IT on my LAN side, my server is handling DHCP right now. I have also created some firewall rules to block torrenting during certain hours and it is working PERFECTLY for me… with one exception.

I now need to make small DMZ test network that doesn’t have the firewall rules attached to it. and I need that network to have DHCP enabled. is there an easy way to do this? I want to make sure that the two ports DO NOT talk to each other. Or do I just have to break down and buy a second router board and pull two more lines from my modems?

Thank you all for your help!