Sounds like you have 2 issues - gaining the permit to ride and buying a bike to learn to ride on.
Firstly, just get your learners as you don't need a bike for this. Even for the Ps test you can hire a bike, although you may not pass the test without prior experience or practice during your learner period.
This is where your wallet/time/need for riding comes in. If you're looking for cheap transport, doing 50-100kms/day and at higher speeds then you'll want a road/sports style bike as single cylinder dirt bikes are a bit painful on the road, high revs, lots of vibrations and alot of work for 1 cylinder. If you were right in the city and doing less/slower kms then the motard/dirt bike/more up right riding position helps and honestly, buying anything with wide bars as opposed to 'clip ons' found on road/sports bikes is going to be better for your control over the bike, again advice more for the learner.
If you had the time/money and didn't need a bike to get to work/commute on then I'd recommend finding a cheap trailbike and doing some riding around the trails. Even if you're not mad keen on dirt bike riding this will give you some of the skills you'll need without having to play out in the traffic. You'll conquer changing gears/throttle control to the point where it's second nature and one less thing for you to think about when learning to deal with traffic because that's nearly an artform in itself. You don't want to be thinking about how to change gears or which lever is the brake/clutch lever when facing a Bus who's about to T-bone you.....
Something you've not mentioned but is fairly crucial to your bike choice is the type of riding, your age/height/weight because a CBR250 for a 7foot/150kg giant won't suit same goes if you're 5foot flat and 40kgs dripping wet.
A taller dirt bike isn't going to be for you and you'll need a low seat height as a mandatory....
If you have the time/money but are more interested in road bikes/not wasting time dirt bike riding then do a few of the Stay up right advanced courses to hone some of the skills like advanced braking, advanced cornering and body position etc.
2 bits of advice for the wise......
1. Always, always, ALWAYS, treat every vehicle as though they're out to kill you. Even if you're going down a straight road, have 'right' of way and have seen the driver waiting to pull out perform a headcheck - assume they have NOT seen you (or have misjudged their timing), you can simply roll off the throttle, cover the brake as a 'just in case'. This is important on smaller bikes that don't have the power to get you out of a tricky spot.
You will become a little more paranoid on a motorcycle and this WILL save your life one day. As will:
2. Always, always, ALWAYS, give yourself an 'option out' - even when or maybe especially when you're stationary. Sitting at the lights in the middle track of your lane RIGHT up the clacker of the car in front gives you no room to move if you see a semi with locked wheels/smoke approaching your rear. Give yourself a little space/buffer room, you could lane split and avoid becoming a cars new bonnet emblem.....ideally you should always be scanning down the road as far as you can and giving yourself several options.
Hope you find this advice useful, unfortunately I am one of those die hard, love 2 wheels types so I apologise for the essay! Post up a pic of your ride in the BIke forum section when you're ready!
