upgrade macbook pro hard drive ssd mid 2010 15 inch

I want to avoid the whirring and crashes that are somewhat unavoidable with my current setup. While considering my options, I spoke with a phone rep at Apple who, after reviewing my needs and options, recommended that, rather than buying a whole new computer, I upgrade from my current 4 GB of RAM to either 8 or 16 GB (I know 16 is really a lot, but running music editing software is really an incredible RAM suck, believe me). As a result, I have begun to explore the idea of updating my hardware to a new Mac – perhaps a desktop model but I'm not necessarily married to that idea, as my sense of the benefits is somewhat vague, having to do with a 'dedicated workspace' and that kind of thing. However, recently, I have been using Pro Tools 11 Music Production software, as well as the Music Composing application MuseScore and I have found that I am not able to get the level of real-time processing speed that I see in some other small home recording setups I have encountered. This was an amazing computer when I bought it and it continues to work quite well for must of my needs. So, to begin, I have a mid-2010, 15 inch MacBook Pro with a 2.66 Ghz Intel Core i7, 4 GB RAM (1067 MHz DDR3) and an NVIDA GeForce GT 330M 512 MB Graphics Card. I know that this is a topic that has been covered in some detail, but I was hoping to get some feedback from people in the know regarding my specific circumstances and the most reasonable course of action.

Upgrade macbook pro hard drive ssd mid 2010 15 inch