So you have a Sitecom wireless router but which model?, The connection you have between your pc and laptop confirms only that you have a wireless connection from the router not a connection to the internet, first of all is your laptop showing any wireless networks in range at all? If it is then it may be safe to assume your laptops wireless settings are ok and would lead me to assume that the internet connection problem is the fault of the router, log into your router and check the settings, you may have to tell it that you wish to connect a wireless client which in this case is your laptop.
For the WPA PASK (wifi protected access pre shard key) go to this website>>
http://www.kurtm.net/wpa-pskgen.
My advice is too copy and paste and save your key because you will need it to enter into your router and for each wireless client you wish to use wirelessly, also remember to change your routers default password to something else, I used the key generator for that too.