Avoiding Proxy in Different Browser Client Configuration Question

Hi,

I am a store owner of a NAPA. We have 5 windows clients..
The network that NAPA requires is as follows..
Cable Modem>Net Screen>Switch>Clients which are set to use a proxy in IE proxy.XYZ.com.

This network is necessary for parts lookup.

However, IE web browsing is extremely slow. And as I understand, all traffic goes to Atlanta thru NAPA's servers.

I have a different network, on a dry loop from Verizon with a static IP, for CCTV, VOIP, and Free WiFi already set up.. Completely isolated.

Any suggestions on how I can configure a different browser to say use a different NIC, say a wifi card, to browse internet only, on the different network. WO touching the existing settings in IE..?

My only solution I think is to set up a VM and configure it to use a USB WIFI adapter... Is there a browser/plug in combination I can use? I am not familiar with Proxy Servers.. Perhaps configure my "free Wifi" router to be a proxy server and get a chrome with proxy plugin? I am reaching?? Any help is much appreciated... These clients only have 512Mb Ram and XP so I am not inclined to go the VM route for counter people..

Can you connect to the NAPA proxy over your Verizon connection?

We pay Verizon for 2 internet services..

Normal internet.. Except NAPA's Network setup as I described...
CableModem(1)>Netscreen>Switch>Clients... These clients have to have IE Connection setting LAN Settings Proxy server set to NAPAs specific proxy...

Completely separate, Internet access, on a dry loop(DSL), different cable modem(2)... <This is set up for Customers Free WiFi and other stuff, CCTV, etc. The router to this connection I have complete access to. This connection is fast, responsive. I want the clients that have to remain configured to use NAPA's setup, to have a browser that can surf the internet using the other access I pay for to verizon, different subnet, different LAN all together. I am willing to purchase new NIC's if its possible.

Thanks....