Optimization of two separate molecules is a trivial task (b3lyp/6-31* opt) gaussian, however two different molecules in combination in one solvent is a different thing. For that you need to calculate the efective fragment potential for each molecule and optimize the position of each other as a function of the other potential. I don't know if G03 is able to do that, but it is possible. It just take a few minutes (I mean in Linux 64_x86)