98' taco 2.4l

Just recently purchased not only my first Toyota but my first Tacoma. Was happy to join the community and get acquainted with my vehicle. Although on the first day of driving after it was purchased was fine, I would soon begin to experience issues such as overheating and a coolant leak. As I got into my research which lead me to this forum and began taking steps to address the problems at hand another had arose. White smoke...out the...exhaust. I believe it is a head gasket leak and I have now contacted my mechanic about handling this issue, however I am wondering if these are tasks I can handle without the need of a mechanic and whichever way I decide to go, what would be a good and reliable source to order parts from?