Thanks for the responses so far. Sorry I did not think to post the specs on what I want to power. I also could be going about this wrong but it was the best idea I could come up with the be able to have something monitoring the battery life and power the other 2 boards easily.
Board one: gumstix summit expansion. ( I eventually want to have the arduino send a low batt warning to the summit/overo by i2c which I already have it doing with a different arduino )
http://www.gumstix.com/store/catalog/product_info.php?products_id=215&show_tab=details
its a normal plug for a wall wart adapter with these specs
rating: 16v DC @2.5A
Contact resistance 30m OHMS MAX
insulations resistance 50m OHMS MIN 500v DC
voltage withstand 500V AC RMS for 1 minute
life 5,000 cycles
The board itself has a 5v 50mA regulator and a 17V 1.5A synchronous step down converter
The second is:
Macally powered 4 port USB hub
http://www.bhphotovideo.com/c/product/551641-REG/Macally_TRIHUB4_TriHub_4_Port_Hi_Speed_USB.html
the only info I can find on that one is that the AC adapter specs DC output 5V 2A positive in center
As far as the 3V part goes we can just scratch that as it was just me planning for the future and had some thoughts on things to add that were requiring a 3v source. So this is not really as important that I figure out now as I can come back later.
Please let me know any other info I can provide as I am happy to do any work to make it easier for the help from everyone. Thanks again and for taking the time 