how to use jffs2 to extend firewall space

Hello all;

This is my third forum and 4th week I cant find the steps to acheive this.

I have a linksys wrt54gs v 1.1 with DD-WRT v24-sp2 (08/12/10) std-nokaid installed.
The purpose is to use the firewall to drop spam ip blocks ,I have a apache server behind the router on a windowxp machine.
I have run out of nvram and enabled jffs2 and CIFs to create more space,,, I have 3.4MB on jffs and and plenty on the CIFs drive.

I am stuck now because I know squat about Linux. I just want to use this extra space to continue my firewall with iptable lines like this

iptables -I FORWARD -s 65.75.240.0/255.255.240.0 -j logdrop
iptables -I FORWARD -s 84.10.154.0/255.255.128.0 -j logdrop
iptables -I FORWARD -s 74.115.208.0/255.255.248.0 -j logdrop

I believe I have to telnet something into the router but am cluless of what.
I bricked 2 routers and am gunshy now Please help and tell me what to do...

Thanks