How to improve quality of (live) stream on my computer?

Hi, I've got BT Broadband wireless connection, which moves between 36 to 54 Mb/s, but when I watch live sport on my laptop (mostly from Czech) it buffers quite often, sometimes every ten seconds. My mates in Czech are fine on those servers with weaker PCs...I believe with this speed of my connection I should't have any troubles and should be able to watch good quality stream, what do I do wrong? Tips, tricks, configuration anyone? If it's any help I use www.fotbalzive.cz or Sopcast channels...many thanks!