Yes, the C8/I8 are rated at 2.5A (2500mA). The connector is something odd, I think I posted it elsewhere after digging it up one time... it's 3.5mm x 1.3mm if I'm not mistaken. Fortunately, that connector size is a little more common than the C1/I3.5's!
As for connecting to the board itself, are you still keeping your I8 in its housing? If so, I might suggest adding a "pigtail" to it -- solder wires (about 6"-8") to the board, tie a knot in them about 1.5"-2" from the solder connection (has to be big enough to NOT fit through the hole), feed the end of the wire through the hole in the housing, then solder a standard-sized (like 5.5mm x 2.5mm) connector on the pigtail. It's not pretty, but it keeps any strain on the cord from stressing the solder joint. I did this on my laptop once -- the soldered-on connector died about a year after I bought the laptop... the pigtail lasted 2-3 years, until I scrapped the laptop for parts because it was too slow