Your DMR-eh57 is the baby brother of my eh67.
You might be lucky, and the player may just work with region 1 or 2 DVDs; I purchased mine from a US reseller, and though it was marked as Region 3 only, it worked fine with Region 1 discs.
Check the instructions at the following website:http://www.dcevolution.net/panasonic/
Though there is a focus on some specific DVD players, there is also a recommendation that the remote control mod (using a different learning remote) can make most any Panasonic recorder or player region free.
Unfortunately, there is no way to simply use the eh57 front panel or remote to do this. You need to use a remote that is able to send out the Panasonic service code. There is also a website in the UK that goes into more detail on region code modifications:AV Forums Hack thread