Help me reconfigure my home network

Factual Questions
1

I live in a two story house and need to put a network connection downstairs.

Currently I have the following hardware

  1. A Linksys RT31P2 connected to the cable modem. This is used for my VOIP Phone ServiceIt is assigned ip 192.168.3.1
  2. A Linksys WRT54GS with Firmware: DD-WRT v23 SP2 as my wireless access point. It is connected to the RT31P2 It is assigned ip 192.168.3.2

I’ve drilled a hole in the floor and ran a patch cable through it into the garage and then through the garage wall another hole so the cable ends in the den.

I’d have a Hawking Networks wireless router with 4 wired ports that I would like to use there. If I can only use the wired ports that is alright but I’d like to use wireless as well because I don’t get a strong signal downstairs.

What is the best way to configure what I have?

edited to add I havea Netgear 10/100/1000 switch which I believe has the cable running downstairs I have to check.

2

Too late to edit again The Hawking Router is HWR54G