When I had to convert my non-JAR license, I visited several flight schools around Czech Republic, and chose
DSA in Hradec Kralove, which made an impression a notch above the rest. My subsequent experience at DSA and elsewhere in Czech Republic only reconfirmed that first impression. Their current prices are
here (25 CZK ≈ 1 EUR). Feel free to message me with any questions.
In terms of duration, you need a minimum of 45 flight hours (which is used as a basis for the list prices), but count on actually doing it in 60-70. The practical exam is held right at the school (DSA has its own examiner), the theoretical one - at the CAA. Obtaining a license afterwards takes a 10-minute visit to CAA at the Prague airport with your signed practical exam record.