Converting front garden for parking

As the thread title suggests, we're looking into converting the front garden of our terraced house in Bromley into parking for two cars. Can anyone suggest a reputable company to do this please? Also, any clues how much it costs these days? I realise we'll have to sell one of the children just to cover the cost of dropping the kerb, but that's fine as I've already decided which one is the most easily dispensable.

Thanks in advance people. :)