So I asked this question on this site and got this answer. Now that I'm rooted, I'm ready to take this route. I've tried looking for ways but almost all the results that came up were unrelated. So yeah, can anyone give me a lending hand with regards to using my Internal Memory as additional RAM for my phone?
You don't need to use 3rd party things like a swap partition or zRamSwap. 512MB RAM was/is still standard and will be sufficent for almost all scenarios most probably for some time (at least for Android 4.0 and 4.1, see this CyanogenMod forum post).
(You stated in the comments that your Xperia Active has 512MB RAM)
To begin with, "ROM" is basically a false name for the system partition and means read-only-memory (it's most of the time mounted read-only, hence "ROM"), this sits most probably on some kind of NAND flash. RAM (random-access-memory) is 'working' memory that is really fast but volatile in comparison to NAND flash. Both types are needed (fast vs. persistent) and cannot be interchanged. At least not completely (you could add a swap partition on custom roms.)
At first: Don't use the internal memory as swap! Flash storage (NAND) has only about 10.000 write cycles. Better use your sdcard for it. See this guide on XDA for the pro's and con's and howto do it. If you just want to play around and wonder if you could do something useful with the free space on your /data partition: Don't do it. Leave it the way it is.
Here's a basic picture illustrating a regular architecture.