Encontrou isto na pilha
I was looking to do this myself just now. What you want to do is set the "roaming aggressiveness" of you wifi adapter. You should be able to do this by
going to network and sharing center select change adapter settings select your wifi adapter and select properties click the "configure" button on the popup window (network tab) click the advanced tab if roaming aggressiveness is there, set it to "highest. Your laptop should now seek out the strongest signal.
No Ralink, existem configurações semelhantes à Intel, exceto pelo fato de o Ralink usar o nome de roaming em vez da agressividade de roaming: