I'd suggest buying Euro every week or so (keep an eye on the currency and trends, lots of info on xe.com). This will even your average R to Euro out and get rid of any nasty fluctuations.
I bought dollars before going overseas, the morning after a 14 hour flight, I exchanged it for the local currency and found I was R4000 out of pocket due to the rand being volatile.
If we had an effective government, I wouldn't give the same advice I do now
