your only options is to buy a Sony's YPbPr/RGB Component Cable and a RGB-VGA Converter. Then also, check if your monitor is manufactured under year 2005 (Sync-On-Green, if your monitor dont have that feature, you might get a darker and flickering on your screen, because the PS3 and your monitor is not synced properly.).
Then once you match up the cable between you PS3 and VGA Monitor. Go to your Video Settings and choose RGB and the cable option. Then after that you're on VGA..
Model: CECHC04 PAL/EUR 60GB SKU Console
Firmware: REBUG 3.55 CFW [DEBUG MODE, DEBUG XMB, MENU OPTION 2]
BM: Iris Manager v1.2 (Hermes Syscall8)