Here all of the firmwares I could find.  Please email me if you find good firmwares for the rg1000 AP. 

rg1000@vilos.com

Rg10383.bin -  RG1000 Version 3.83 - tested rg1000 ok
ap05384c.bin - AP500 Version 3.84c - tested rg1000 ok
AG1XV386.bin - OR1000 Version 3.86 (DOES NOT WORK ON RG1000!)
wpnt384c.bin - AP1000 Version 3.84c  did not work on rg1000
wpnt383.bin - AP1000 Version 3.84 (A?) did not work on rg1000
airport_1.3_firmware.bin - tested rg1000 ok 
airport_2.0_firmward.bin - did not work on rg1000