Center+Satellite speker recommendation

Hello!
I currently have a stereo system which is fine for listening music (suits my needs for now). I want to accompany it with a centre speaker and a pair of satellites for movies. I don't want to spend too much but also don't want the new speakers to mess up the sound quality I can get from my current system. What speakers would you recommend?
My current system consists of:

• 1) Pioneer VSX-416 receiver
• 2) A pair of RRR S-400M speakers - it's a locally well-known manufacturer, but, I guess, little known worldwide. Here's a link to the specs: http://www.rrr.lv/en/products/acoustic-systems/s-400/9
• It says the resistance of speakers is 4.8 Ohm, which is not true - it's adjustable from 4 to 8 Ohm.
• 3) A Yamaha YST-RSW300 woofer

The room is something around 20 square-meters (200 square feet)