DD-WRT vs. inSSIDer Wi-Fi Helper: Does this make sense

In looking at tools (therefore reading info on websites) regarding improving wi-fi reception I came upon both DD-WRT and inSSIDer Wi-Fi Helper. But a comparison between the 2 showed no results this telling me that these 2 software are probably for totally different uses and therefore not related. I was wondering if anybody could shed light on the difference between the 2. Why use one or the other?
My network, being a home user, involves 1 PC, 1 laptop, 1 android tablet and one smart phone (and yes occasionally there may be guests over so all but PC will increase.
My reason for reading such articles is that my reception isn't as good when I am in the back yard (or kitchen next to it) as well as my bedroom (the room behind my PC location) and I was therefore looking into how to improve reception, and the above 2 names popped up (also: Tomato, OpenWRT and related Wi-Fi Stumbler, Wi-Fi Analyzer).

Thank you

Thanks for your input Dude [Dude!!! really?? ]
I'm hoping now that someone can tell me the difference between the 2 (or others)
99% of the time I don't use wi-fi at home (it's mainly guests) so a question that came up, which I had not asked originally, was if this would affect my original ethernet-cable plugged-in PC in anyway; by fooling around with other things such as those mentioned.

DD-WRT is an open-source replacement for your router's firmware.
A router is actually very similar to a PC, and the firmware is the OS. DD-WRT is based on Linux and installing it is kinda like changing from Windows to Linux on a PC. What this means is that you can get access to features not found on what the manufacturer (or ISP) decided to allow on the router.
It doesn't work on all models of routers, so you'll have to check. Moreover, if you do not own the router, you definitely should not use it. It's similar to opening or modifiying a router leased to you by your ISP and is a breach of contract.

inSSIDer Wi-Fi Helper is a program to check what is the best channel to use for WI-FI. You have to install it on a PC connected by WI-FI and it will give you stats and recommendations on each WI-FI channel signal strength, and give you stats about your neighbors WI-FI usage. It's a nice app if you have difficulty finding a good channel in an environment full of other WI-FI users competing for the same channels. If you only use wired Internet though, it's useless.