None of the cheaper rebadged brands will do you any good. Stay away from Dixon, Ecco and the like that you find at Cash converters, they won't be able to power those speakers properly and will sound terrible.
You say stereo configuration with 4 speakers? I assume you just want to hook up two to each channel. If that's the case look for one of the mid range brands like Sansui, though don't expect that amp to power your speakers properly.
If you have the money and some luck, try look for an old NAD amp(I have two stereo ones, a 3020 and a 3140) and even though they're rated at 20w and 40w respectively they smack cheap brands out of the park in terms of power delivery and sound quality. Pioneer is also a good brand to look at. Budget around R500 - R1000 for one of these depending on how lucky you are.
With audio, if you buy sub standard(crappy) equipment, you'll often have to deal with sub standard(crappy) sound.
Also, "The weight is a sign of reliability." - Boris the blade. If you want a good quality, reliable amp, get something that's heavy.
