you can search map here: http://center.mtasa.com/?p=search
when you found the maps, you can klick on "Add search to feed" and then, the maps are in your feed. then go to rdd feed (http://center.mtasa.com/?p=search) and copy the link of your feed. at last, you open the config file in your server directory and fill in the link you just copied.
FILL IN THE LINK HERE
120
mods/race/maps
50
500
then start the rssmapdownloader.exe