Ridiculously High Ping!

Ityshow

So my friend and i both love crossfire but we are unable to play together at the same time. We are both sharing the router but my mothers laptop which he uses to play at my house has ridiculously high ping between 400 and 4500 when we are both in game (me on my laptop) im not sure if it is my moms laptop as im always on before him maybe it cud b a one pc per address on a server or w/e ( if that could b a problem) i just wanna kno if i cud fix the problem ive tried the most common problem solutions when it comes to ping issues but it is still there can u guys help me.....btw my moms pc is way better than mine but my laptop plays lag free with 150 to 200 ping range (norm) my mom's goes clean to but ping is rlly high.