Help with data transfer please

Hi All!
I don't know if this is the right place to post this, but if anyone knows databases-you all do!

In brief, I'm open to suggestions to the cheapest most reliable way of either maintaining two seperate postgre servers or of using one server from an office 30 miles away.

The long version:
I have my postgre database running smoothly in my rural office, ( i.e., only telephone connections to the office). I'm about to open a second office 30 miles away that does not currently have internet access, but could. I will be alternating offices on an every other day basis and it is important the the information in the "database" goes with me so my staff can update it where I am. However, although I've now written the internent programs necessary to access the single database (currently in the rural office), AT&T will be more then happy to charge a small fortune to maintain telephone connection (long distance) between the two offices. Since I'm initially expecting zero income from the new office, it is not feasible at this time to be calling the rural office via telephone due to telephone costs. Also, I might add, no-one will be in the rural office durring the time that I am in the new office. The database uses many sequences for record uniqueness. Thus simply transporting the new or modified records (via floppy) would leave the sequences corrupted (I think??).

I'm sure this has been solved many thousand of times before, can someone please suggest a simple (cheap) solution?

Thanks,
ajw