I'm thinking about upgrading my desktop PC. It's 3 years old, and I mostly used it for programming, a bit of gaming and things like that. I had no problems with it, it can run the newest games, not at full settings but it can. But now as I'm going to attend university, I'm thinking about giving a boost to it. 

Specs: 

* Intel Core I5 3330 CPU
* Sapphire Radeon HD 7770 GPU
* 8GB Corsair Vengance 1600MHZ DDR3 RAM
* 120GB Samsung 850EVO SSD
* 500GB WD 7200RPM HDD
* Asrock B75Pro3 motherboard
* 500W PSU
* Extra: 8 yo. 1440x900 LG Flatron monitor

I would like to do modeling, and game development as well, because I have these options at university too, and still can't decide what should I learn.

Additional info: I have a "work/travel" notebook as well which has the following specs: 

* Intel Core i5-6200U CPU
* 4GB DDR3 1333MHz (I'm not sure, and I think it's not really enough for anything big)
* Nvidia GT920M GPU
* 500GB 5400RPM HDD
* screen resolution is somewhat below my desktop

I'm awaiting ideas about if I should upgrade and if yes, then what parts are the most important. Or if I should sell the desktop then why, what should I buy from the money from selling it, etc.