Having some Internet connection problems , what can i do to stop them happening . ( PS3 )

Right it’s my PS3 that has the issues , it works fine up stairs this id done wireless . And its furthest away from the modem router a Thomson livebox mini , Yet when i connect it wireless downstairs in the main room it is hard to play certain game modes on certain games . After a while i get disconnected from the network , or the game universe this can be when waiting to Q for a game it acts like it times out .
I was thinking on buying a Powerline ’ Belkin F5D4076uk 1Gb Powerline Adapter ’ to be exact , thing is would i need to buy a 1 GB size or less my internet is as said by the provider 6Mbps , yet while wirless on the ps3 only gives me around 1 or 2 MAX . Should i buy the 1gig or should i buy less cause the gig wont do anything ?
Maybe there is something i can do that doesnt cost too much cash like the powerline does ( not that cash is an issue ) I cant go wired as that would mean calling in an engineer to re route where the phone access is located to the livinroom . As far as i can see powerline is my only option but what one to get…...... PLEASE HELP