ExcelBanter - get external data - new databse query speed help

Hi,

I will try and explain this as clearly as possible.

I have 100 users each with a local copy of a s.sheet I have created.
This spreadsheet is 'synchronised' by the user to retrieve up to date
data from another spreadsheet located on a secure network.

When synchronising the local sheet basically;

1. runs a database query on the remote network sheet
2. queries for records matching a certain criteria (normally 1000 -
1500 records match out of approx 150000 records in total)
3. copies the matching records
4. pastes the records into a sheet on the local spreadsheet
5. updates the local sheet with the newly retrieved data

My problem is that steps 1 to 4 (not including the updating) can take
around 3 minutes (on a broadband connection). (If the user is in the
office ie. directly connected to the network it takes approx 10
seconds).

I am looking for any methods of retrieving the required data across
the network that would be significantly quicker. (Originally when I
first wrote the sheet it would open the remote sheet, filter the
records and copy the matching ones before closing the sheet and then
pasting back into the local sheet. This seemed to take longer than the
current method).

One of the thought lines I have been having was whether it would speed
up the process if the only records retrieved were the ones changed
since last 'synchronisation'. This would be c. 50, instead of
retrieving the whole set of records (1000 - 1500). Would this work? Or
is it the querying that is slowing the whole thing down? Would it be
quicker to bring back 150000 records without querying them, and then
delete the uneeded ones once they were in the local sheet?

Any suggestions much appreciated.