EOC-2610 is supported by dd-wrt. If you want to be on the safe side, look for the suggested build in the supported devices database.
If you feel adventurous, look in the download area, to the latest development build at http://www.dd-wrt.com/site/support/other-downloads?path=others%2Feko%2FBrainSlayer-V24-preSP2%2F2011%2F05-08-11-r16994%2Fsenao-eoc2610%2F (As of 21 May 2011. Later date may give newer firmware).
For flashing, configuration as repeater etc, look at wiki and at your router's flashing instructions that you find in the routers database.
In general, dd-wrt supports repeater mode.
BTW, your device is on the "require registration" list, that means you need to purchase the activation as it is considered professional router.
