Your best bet is going to be teaming up with somebody who does this sort of thing (electrical/mechanical prototyping) for a living (there are a few individual consultants and small consulting firms, some of them suggested elsewhere in this thread).
1-2 cm^3 is going to seriously limit the consultants who will be able to help you, and the manufacturers who will be able to produce the thing. The consultants specialize in low-volume designs, which typically mean that size and efficiency are not first-order concerns. Likewise, quick-turn PCB houses are not likely to make you 1 or 2 of something this small, as their tooling is not set up for it (not the common case for their market), and I would imagine similar constraints are present on the mechanical/assembly side.
If you feel comfortable learning PCB design, at least to do the non-space-critical "other components", these are some good resources:
http://www.alternatezone.com/electronics/files/PCBDesignTuto...
http://www.pcbdesign.org/
http://www.smps.us/pcb-design.html
As far as software, you can try PCB123's (http://www.pcb123.com/) free software if (and only if) you want to use them to manufacture your boards. Otherwise, I'd go with Altium Designer (http://www.altium.com/products/altium-designer/en/altium-des...) (used to be Protel) personally, but other options are gEDA (GPL EDA suite), Orcad, PADS, and Eagle. Other than gEDA (obviously), the for-pay CAD packages are pricey, though there are usually student discounts if that applies to you.