Hello , you could block pave over the concrete
so lighting would be nice and patio heater/log burner to keep warm !
I would get a few garden design books out of the Library for ideas
what ever you do best of luck
You could always combine a little corner - bottom right of your pic - with the path so that you can have room for a seat there too.
Take your time with it - do a bit of planning and thinking so that you have what's right for you and your needs. There's a seed swap thread here too so you can try growing some stuff yourself to save money