When I go into the service status part of WHM, i'll usually see 80-90% memory usage, and something like 0.192 % swapfile usage.

If I click on the link below that (server information) I see this:
Total Used Free
Swap: 1052216 846684 205532

Which makes me think that I've used 80% of my swap file, thus I need more ram.

Which figure should I believe? This machine has 512 mb ram currently.

Linux does not work the same way as Windows when it comes to Memory Management.

In Windows, memory is allocated only when it is needed.

In Linux, memory are allocated fully to swap and other components when available thus it looks like you consume all the memory. But in effect, you are not.

In SSH, tyep VMSTAT , check the SI and SO figures, they shows the Swap In and Swap Out (in Kilobytes). If these figures are low, it means that you are still not utilizing the swap yet.

True, in your case, 0.192% is the swapfile usage you are using of the 100% which was allocated to it.

You are doing fine and do not need to add more RAM if you do not want to do so.