Well you need at least 45 flying hours for the PPL - assuming the weather is good and you can do 5 hours per week, so...
Theory can be studied and tested in parallel, you should aim to have that finished by the first third of the flying time, because the test is usually required before you're let off on your solo cross-country flights.
Depending on the plane you fly during training, how many hours you really need and what learning materials you choose to get (and maybe a decent headset?), it should cost somewhere between 8500 and 12000€.
You can do the maths for NVFR yourself based on that - iirc it's about a tenth of the flying hours required as for the PPL?
I don't really know the area around Gießen or Frankfurt, but you might want to check out the flight school at Egelsbach near Frankfurt - depending on whether you're planning to learn German, you will need a sufficiently large airport to fly from so that they understand English. This will also factor in the cost of getting the license, because if you mostly fly to large airports during training, the landing fees will be a lot higher than for small ones. The theory test can be done in English
AFAIK, also you will need to plan for the AZF radio license (if you're aiming for ATPL anyways), plus get a language proficiency certificate that you actually can speak English. Both together should come at about 500 to 600€.
I might have forgotten a couple of details but that should cover the basics...