adding more ram is not a difficult task because ram memory chips simply plug into sockets on the motherboard.
however, it can be tricky though, because it requires to open up the computer. then it requires an understanding of the motherboard's particular configuratoin needs when it comes to memory.
some motherboards have specific requirements for memory.
so the first step is to review the computer manual on the section for memory configuration and see if you can add more ram to it, or if you need to take out that small 256 chip out and simply use a larger chip, like 1 gig ram. (for regular computer users and xp, it is not required to have more than 1 gig of ram installed)
in regards to the safe mode. you can't connect to the internet because it is not permitted. however, in safe mode with networking you can, since the internet is a world wide network.
the reason why safe modes are performing better than in normal mode, is due to the fact that non microsoft programs, ie third party programs are prevented from loading into memory and running.
as the result of not having additional programs the windwos (by itself) is able to run ok in / with the small memory chip.
on the other hand, in normal mode, windows + third party programs are loaded into your small memory chip, and it is bogging down the system.
so at this point, you could try to eliminate some of the programs that are automatically starting and running in memory for normal mode windows to get some improvement in performance.
the method is known as "clean booting" and here are the steps:
http://pcsmarties.wordpress.com/cleanboot/
but the method above plus adding more memory to your computer, is the way to go.
incidentally, if you are going to execute a clean boot, be careful not to disable the start up programs for anything that is toshiba, like mouse or keyboard.
on some laptops, the drivers for the mouse are loaded at startup and you might have to plug in a regular usb mouse to get some mouse function back until you can re-initialize the mouse driver.
also, you mentioned that malwarebytes found some infections. although this is a good thing, it is hoped that the infection didn't corrupt any of your window system files.