Hi I know of nice safari company who can help you with bookings/reservations for accomotation in kruger or a trip in the kruger.The do small groups from 2 - 6 people.so if you are 2 people they will take you on your own.Very flexible.
3 nights kruger stay + pickup from JHB airport is about 300-350 pounds. Thats all inclusive breakfast + diner + nightdrives in open game viewing pickups.
Or if you want to go on your own you can hire a car drive to kruger about 4hours drive.Toll Fees will be about 15pounds then you will pay for a nice Luxury Walk in tent(got 2 beds +fridge,fully equiped)in one of the kruger's camps about 20pouns per night and an extra 12pounds per night conservation fees.Nice camps are Skukuza, Berg en Dal or Lower Sabie.
Hope it was helpfull.Check out the source.