Internet Connection Problems Please Help?

[MARINES]

So I have an internet connection that works fine most of the time. In my house I have around 2 Laptops that use the wifi from my house. I have 2 Laptops using connection, 2 Iphones SOMETIMES using connection for wifi and an Itouch using connection. So MY PROBLEM IS..... Everytime I wana play on my Playstation 3 and go online it works perfectly fine... BUT WHENEVER my sister goes on her laptop online I always lose connection from my ps3 OR LAGG REALLY BAD. Her laptop is a Sony Vaio, My other laptop is a Toshiba (I DON'T HAVE A PROBLEM WHEN SOMEONE USES THE LAPTOP TO GO ONLINE WITH THE TOSHIBA) I ALWAYS HAVE A PROBLEM WHEN THE SONY VAIO IS BEING USED AT THE SAME TIME MY PS3 IS BEING USED PLEASE HELP

[spartan545]

Im not an expert on internet connections, but if I had to say it has something to do with Sony. PS3 is a Sony product. Perhaps the two products cancel each other out.