The Crestive Aurvana Live looks like an excellent choice.
Being in Poland maybe you can shop from Amazon UK? I'll check some prices for comparison.
For only PC gaming with the Aurvana the Xonar U3 is good as it has Dolby Headphone and has a good headphone amp and good price and quality for what you need. Optical out too if needed. No volume control though and no stereo speaker output. (£30)
The internal Xonar DG has Dolby Headphone, rear 5.1 ports for your speakers and looks like a pin to connect a front headphone port on your computer for convenience. Being internal all volume control would be through windows which is not ideal in gaming. (£23)
SBz does not use Dolby Headphone but I think their own version of SBX surround which I'm not sure works for game surround but perhaps only prerecorded audio. It has rear 5.1 outputs for your speakers but no pins for a front headphone port that I can see so only a rear port for your headphone which would be problematic for switching, and again being internal all volume control would be through windows. (£50)
The U7 is the most expensive, uses Dolby Headphone virtual surround, 7.1 rear ports for your speakers, a front headphone port. Being external it has volume control on the top and easy switching between speakers / headphones by pressing the wheel. (£75)
I've taken a closer look at the Recon3D and it seems like it's could still be an option. It uses THX rather than Dolby Headphone for virtual surround which I assume is similar for the xbox but I'm not sure if this virtual surround works for PC games or likely only stereo. It has volume control, optical in for xbox and USB in for PC which can be connected simultaneously. No speaker outs though (£60)
In the end I'd likely stick to Dolby Headphone so an Asus would be my choice, most likely the Xonar U3.
Actually, I've just remembered what you need for your xbox, the Turtle Beach DSS2. It would be better than the Fiio for gaming. It has 5.1 Dolby Surround processing for any optical 5.1 source like the Dolby Headphone on the Asus, volume control and even secondary stereo inputs for your PC that has stereo virtual surround (which is not as good as Dolby Headphone surround from the optical 5.1 source) In fact, you could combine this with the Dolby Digital Live optical out on the Asus U3 too to get headphone volume control on the PC (£50)
I know there's no one item that is perfect like we would want, but there are some options for you to consider.