Linking Possible

I have a RouterBOARD 951-2n. I am new to this and wonder if the following can be done.

I have an existing computer at IP address say A.A.A.A. This cannot be changed. I have an existing WIFI network with addressing in the B.B.B.* range. I would like to connect the Routerboard to the computer. Then by accessing my existing WIFI with an address of B.B.B.* which would then connect to the Routerboard wifi and translate that address to A.A.A.A.

In other words: I enter B.B.B.*, this goes to my WIFI, then to Routerboard WIFI, then to A.A.A.A.

Is this possible and can anyone give me some starting points to configure this?

Thanks all.