you say it as if you werent aware that you bought it 🙂
if its an option run WPA instead...more secure. if its not an option, look into a firmware upgrade from the manufacturers site. your client devices would also need to suppor this security method as well.
for the logs, it depends on which type of router you have. Check for a Status tab with a DHCP Client Table or an Associated Wireless Clients list. also check under administration and enable logging, then check the inbound/outbound logs.