Thank you very much for your help. To continue,
I would say that when I'm watching something on my TV ( from the PS3 DLNA connection wireless 2.4Ghz , from my file server witch is connected on a Gb lan port on the router), This become the absolute priority, to be able to watch TV without any lag, stops, etc...
When I'm not, any lagging from downloading, or backup between the laptop/NAS drive is not really an issue, it's not real time "issues" like watching TV.
I would like the wiresse DLNA connection to gain priority any time someone want to watch something over it, without having to any intervention on my laptop, routeurs, NAS device ..

I Live in Quebec, Canada.