artie,
The short answer to your question is, maybe.
Really I am a bit surprised that you are getting satisfactory results with only 128 MB. How much swap do you have setup?
If you are getting memory bound, thats to say you are getting into situations where you are using all your physical ram and all your swap space, then increasing your swap partition size could help you. I wouldn't set the swap at over 512 MB with only 128 MB or physical ram.
You will still be accessing the disk a lot so don't expect a big improvement. It will just decrease the amount of gymnastics the kernel and cpu have to do to keep operating.
Download and burn Gparted. Boot off that disk and you can change the size of the swap file. Be careful though. Depending on where the swap file is located, it may be a major pain to adjust the partition sizes to accommodate more swap, without corrupting something else. If you have some unused space on the hard drive, it might be easier to create another swap file. You can use more than one swap file you know. The operating system will just add the two files together.
When you are done you will need to update the UUID's in /etc/fstab for any partitions that you have changed. You will also have to make an entry in /etc/fstab for a second swap file if you made another one.
Good luck,
Fred
of course.
