Wireless with static IP?

I have 2 computers w/XP Pro running an application which requires them both
to have a static IP. I would like to give one of them internet access
through the wireles lan which exists in the office where they are located.
I'm assuming the easiest way is to install a second NIC (wireless) into
this computer. Will the wireless lan expect my PC to become whatever IP it
assigns and what if someone already uses the IP I have set? At this point I
have no idea what the router is. Will I need to get access to it and make
some settings or am I worrying about something which is already addressed in
the protocalls?
TIA