GPU for media, video encoding/ editing

I´m soon building a PC for Work with spare parts from my old rig.

I work at a small cinema in Germany and will be doing some light editing and encoding/ converting.

The Hardware I got:

Phenom II X4 955, Am3+ Motherboard, 8Gb RAM, some old HDD´s, a Core 1000 case and a power supply (duh).

 

Now I´m looking for a GPU for 50-150 € with good output connectivity (maybe more than one HDMI) and that could possibly save me some time when encoding/ converting MOV, MPEG and uncompressed editing formats some filmmakers sometimes want to look at.

I´m currently considering the Gigabyte Radeon R7 250 OC...

Maybe you guys got some ideas.