I would not use this machine to access "sensitive websites" such as banking, anything were you would use a credit card to purchase, etc.
I would not trust this machine until it has a full format and reload.
I would not share a wireless router with anyone I suspected of having an infected machine. Further I would restrict access to the wireless router using the MAC address of my machine and other machines that I trust.
Check this out:
secure your wireless router
When you get to the end of the article I hope you follow the advice given and you can find everything you need to know on the internet or at the website of your router manufacturer.