Stellenbosch is a student town therefore affordable, larger houses suited to family living are scarce, especially if you require this as fully furnished. However, one can find alternative accommodation in surrounding areas, including in Somerset West, a nearby town (15km from Stellenbosch) with more affordable accommodation options.
It is a short commute from Stellenbosch (if you travel after peak hours!) and has a number of really good primary and high schools.
SU International can assist with advice on accommodation in Stellenbosch as well as provide temporary accommodation for the first few months, before settling into a more permanent place.