Trading in an old MacBook Pro or just upgrading memory?

Hey guys, I'm kind of in a dilemma right now. Let me explain first:

I've got a MacBook Pro 15" Early 2011 (2,0 GHz model) with 4GB of RAM (DDR3 at 1333MHz) and an AMD Radeon HD 6490M (256MB GDDR) I mainly use it for photo editing (Ps, Lr) and producing some video (Pr, AE) and web development (Dw). I also do a lot of gaming - well I wish I would - on a Windows partition running in Boot Camp. I did have a Windows notebook before and upgraded it to the MacBook Pro. For those things I do on OS X, it's perfectly fine, well perhaps, I thought of a memory upgrade. But using it to play Battlefield 3 (yes, I know, a Mac is not a gaming machine) or BioShock Infinite or even the upcoming Watch Dogs, the AMD 6490M is a huge disappointment. Really. It's total crap. Even the model beforehand (Mid 2010) had a better GPU and at least more graphics memory.

That being said, I'm not sure what to do now. I did some research and this machine (I always treated it with care and niceness) is still worth about 950€ at the local reseller. I could just trade it in and (supposing the new MacBook will cost about the same) buy a new one for another 900€, right?

Here comes the dilemma, if I don't act soon, the worth of this MacBook will fall and continue to fall, on the other hand, is it safe to buy a new MacBook now? I mean, when is the next one launching? I know, nobody knows that exactly but maybe there's some folks who can do a fairly precise prediction. On the other hand, I could just buy 16GB of RAM, this won't really bump graphics performance as it doesn't support shared memory but it would bump up overall performance. Especially for rendering video (with the bottleneck of an HDD left out) and multitasking lots of apps as the Swap is currently using between 2 and 5GB.

And the third possibility is to take the 900€ I'd be ready to spend on a new Mac and go buy or build a tower gaming computer. Even if I'm keen on this idea, I'm not sure if it's the best solution because it's not portable (LAN parties, anyone?) and having two separate computers is a pain in the arse.

Summarising it:
Fairly old MacBook Pro 15" Early 2011 with 2,0GHz i7 CPU, AMD 4690M GPU (only 256MB VRAM) and 4GB RAM.

Options:
- Trade in and get ~950€ in cash; add 900€ to buy a new MacBook
- Just buy 16GB of RAM (for ~120€) and enjoy speediness but crappy gaming
(-- Do that and overclock)
- Buy a gaming PC for the 900€ and have 2 computers to maintain.

Having this mentioned, I'd like to mention energy usage, too. As of two computers would consume a lot more energy in a runtime of say 2-3 years. Also, I don't have much space for another computer. And having two computer sucks because I'll have the Mac to do some work on and the gaming computer sitting there doing nothing and being a waste of money which I could have used for upgrading the work-computer.

The fourth option would be, build a hackintosh and install OS X on it. As this would violate Apple's EULA in some extend, this is not preferred even though I've done it before on an old laptop. The maintenance is a pain in the arse and it sometimes run unstably. BTW, I won't pirate OS X or Windows as I own Snow Leopard, Lion and Mountain Lion and I'm likely to get Mavericks; and I own copies of Windows XP, Vista and 7.

If you read through that, I'd like to thank you for spending your precious time reading about my stupid first world problems on having too much money. Haha. In fact, I don't. I just saved some just for things like this.

So, your opinion and suggestions to this?