access point posibility

I hope someone can tell me how to set up a wireless access
point. This is the situation. I have a two story house with
plaster walls, ceilings filled with chicken wire. Because
of this the signal to the upper west area of the house is
between very low to zero. I have a MN-500 and a MN-700 base
station. The MN-700 currently serves the two thirds of the
house that can get a signal and is loacatd on the first
floor. My idea is to run a ethernet cable from the MN-700
to the MN-500 located on the second floor for added range
configuring the MN-500 as a access point. Is this a good
idea and if so how can it be done? Thank You.