The transmit and receive times sound about right for that size of file on a 56K modem. In my experience, a 56K link very rarely operates at 56K, if ever and is often nearer 30K if you are lucky.
Also, bear in mind that there is quite a bit of overhead, in the form of handshaking data exchange, on top of the actual file. If you want to see the effect of this overhead, you can get a rough idea by doing the following. Next time you send an attached file, make a fresh dial-up connection, and when you start the transmission, right click on the little activity icon in the task bar, at the bottom right of the screen and select 'status'. This will open a small window showing file exchange progress. When the transmission has finished, you will see the number of bytes sent which you can compare with the size of the attachment.
I'm looking forward to getting broadband later this year when the powers that be decide to upgrade our local telephone exchange.

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Willum