Fortunately you don't have to buy drivers.
They are just "software" things you can download freely for you graphic or sound card manufacturer web and install them. Like patches.
Manufacturer use to actualize their drivers from time to time to improve the cards performance and make them more compatible with newer games.
If you are not very tech savy, i recommend sending the dxdiag to support so they can take a look at what's the problem.
The game does not ask much computer power. I play all AGEOD games on a 5 year old computer.
Do you have at least 1 GB RAM memory?? under this the games can give problems.