if your network has DHCP it will automatically pickup an address from that so you need to find out what address its been given (normally look into your router) and browse to that address in a web browser.
as for the slow speed, try turning 5ghz off and see what speeds you get on 2.4ghz only, also try putting it onto 40MHz and 20MHz and see if you get better speed.
are you sure its not a device issue? or are you confident its an access point issue?