Alright. So my advice is to first of all sell any parts you will be upgrading such as the PSU and GPU. You will need a better PSU for a R9 380X, about 500-600 watts recommended, and also gives some headroom for other upgrades down the road. Speaking of new technology, AMD Ryzen is releasing the rest of their processor lineup very soon. This will be great for you if you are tight on money because they will have some great price-to-performance processors operating on 14nm technology, supporting DDR4, and many other new things. I think a good idea would be to build a new PC, and possibly sell your current PC to get some cash flow and rebuild a new build with Ryzen, and Pascal. Here's a short list of what I think would be a great build including all the new bells and whistles: (Just for having options open)
CPU: AMD Ryzen R5 1300 4-cores 8-threads/8MB L3 cache/65W TDP/3.2GHz clock, unlocked/ - $180
https://www.newegg.com/Product/Product.aspx?Item=N82E16...
MOBO: MSI B350M Gaming PRO Micro-ATX (Supports OC) - $85
https://www.newegg.com/Product/Product.aspx?Item=N82E16...
RAM: HyperX Fury 8GB (2 x 4GB) DDR4 2400 - $60
https://www.newegg.com/Product/Product.aspx?Item=N82E16...
GPU: EVGA GeForce GTX 1060 GAMING - $192
(For The Witcher 3, this will destroy it b/c the recommended requirements are a GTX 770 or R9 290)
https://www.newegg.com/Product/Product.aspx?Item=N82E16...
CASE: COUGAR Spike Black (I have a friend with this case, super solid, stylish, and aggressive.) - $33
https://www.newegg.com/Product/Product.aspx?Item=N82E16...
STORAGE - SSD: Toshiba OCZ TR150 2.5" 120GB (For OS) - $83
https://www.newegg.com/Product/Product.aspx?Item=N82E16...
STORAGE - HDD: WD Blue 1TB ( For games/media) - $52
https://www.newegg.com/Product/Product.aspx?Item=N82E16...
PSU:Corsair CX600 - $57
https://www.newegg.com/Product/Product.aspx?Item=N82E16...
I really hope this helps, the entire build comes in at around $750, but I added roughly $3-$5 headroom for tax and stuff. So you could be saving up to $30 dollars due to my overkill future proofing. You can also build a PC that is WAY cheaper than this if you want to save money. Though my recommendation is that if you are tight on money, (which is totally fine, you just have to be smart with your purchases.) just save until you have enough to purchase the parts. Limit yourself to minimum and practical things, then you can have the PC you want! I included all the links to Newegg because they are a really good company. You can always find other parts on places like eBay for cheaper.
Again, I hope this helps. If you have any more questions, feel free to ask.
God bless,
~David