I don't think you will have fun playing with that specifications. Onboard graphics of a ten year old mainboard in combination with half a gig of RAM should manage less than 10 fps in situations like bad weather, big convoy etc. My computer is 6 years old, 2,2 Ghz AMD 64, Geforce 7600GS overclocked to max, 2 gig RAM and with resolution of 1280x960, max particles and HQ textures, 4xAA and 4xAF I get about 35 fps in a big convoy. With a 7 year old laptop it was about 10 fps in a big convoy with no AF, AA, low quality textures and at 1024x768. Just to give you an idea how demanding the game is, it was published in 2005 after all.
This is for GWX3, which is a little heavier on RAM but otherwise designed to make it playable on the same systems that manage the stock game.
You should invest a few bucks in a new(er) system
Where I come from you get cheap used systems from like 3-5 years ago for less than your 100 dollars, ebay for example.
Best regards, Gnonz