Strange Speed problem

[epicTorrent]

Sorry if I've missed it, but I did search but couldnt find any threads posing the same problem as mine, here goes

Im downloading from a laptop, getting a wireless signal from a Netgear dsl router, our internet plan is AOL silver (terrible, I know)

Utorrent was working perfectly fine, id get average speeds of between 30 to 300kpbs depending on how well seeded the torrent was, Now, ever since the computer the router was connected to has been changed, (went from xp to vista), the speeds ive been getting on my laptop, and on the pc are much lower, not getting much about 10, even when a torrents well seeded, and the Network icon shows yellow constantly now, but then it used to show yellow seemingly randomly before when I was getting speeds of 300,

Nothing changed on the laptop, so it cant be a problem here,

Ive disabled the windows firewall on the pc, and every other vista protection i could see which could possibly be blocking it somehow, but no luck, speeds didnt improve on the laptop or pc.

Ive tried a few well seeded torrent for a test (100+seeds, 20 leech), and none of them got much higher than 30 or 40kpbs

Now the even stranger thing Im finding, my download speed seems to go up significantly if i have more than one download going at once,

My torrent, which isnt as well seeded, 20 seeds 16 leechers, going at about 2-8kpbs, but then, when I start a well seeded one, 100 seeds 30 leechers, that torrent goes up to about 50, but the poorly seeded one goes up aswell, to about 20-30,

Ive tested this repeatedly now, turning the well seeded one on and off, and its defiantly effecting the slower one, I have no idea why this is doing it

I cant work out whats changed or whats happend, any ideas or advice would be greatly appreciated =]