The way I see it, you have a dilemma (and a rudeness issue, but let's put that aside). You have an old machine that is due for replacement (it's more than five years old now), but it runs well for what you do on it. Upgrading to Yosemite COULD cause problems. But on the other hand, your machine's OS is no longer safe to use because it is longer receiving security updates. This and other problems (software updates that won't work with a system that old, Flash and Java no longer supported, HD video that is unplayable on a machine that old, etc etc) will continue to multiply.
The logical solution is to get a new (or at least quite a bit newer) machine as soon as you can. They'll already come with a newer OS version so that will eliminate those problems. You could also opt to stay where you are -- which is the more attractive option price-wise, but increasingly unsafe and insecure.
I'd vote to replace the machine in the near future.
PS. We're always happy to help people who "don't know what they are doing" -- but it shouldn't be worn as a badge of honour or a defense against the (gasp!) reasonably-put request for additional information (which was requested solely to HELP you). If you're going to get irritated every time someone asks you a troubleshooting question, you're not going to get very far here -- or anywhere.