ok, so with that level of data-transfer you'd be working 3Mb/s hard, presumably they'll be peak times, so 4 or 5 might be needed (mrtg graphing over a few months shoudl help)
so if i was advising you, then i'd say you need a *minimum* 1Mb/s overseas and 3Mb/s local probably a bit more based on your numbers - can you start small and expand at a moments notice or do you have to commit at the outset
i dont doubt your usage will grow to 10mb/s + just wondering if you'd need all that to start with ...