Your English is far superior to that of many regulars here, no point in apologising for it.
Anyway, afaik, you can't. You can run memory faster, but not slower than FSB on the KT333 (at least not on the one I used to have, and it was also an A7V333 if memory serves).
If you really want to hang on to your MB and RAM, you could consider an Athlon MP, they run at 266 FSB, and at higher clockspeeds than XPs with the same PR rating. The MP 2600+ is still relatively pricy though ($127 pricewatch), but runs at 2.13 GHz stock, is multiplier unlocked AFAIK, and should probably overclock fairly well. Depending how much RAM you have, this could be cheaper&faster than a XP 2600+ with new ram, but keep in mind you won't be able to use that memory for your next upgrade, whereas is you bite the buller, and get new RAM, it may serve you next time as well.
= The views stated herein are my personal views, and not necessarily the views of my wife. =