Hi Chan, and first off, welcome to the site!
You will have to take your CBT again as it only lasts for two years, and therefore, you are currently breaking the law!
You will indeed have to do the theory test again I'm afraid.
The best way to go would be to approach a local training school and speak to them about doing your DAS (Direct Access Scheme) if you want to ride a bike with more than 33bhp. You will end up doing the CBT again on your first day, and then move on to the 125cc bikes for the next couple of days. After this, you'll be on a 500cc or so sized bike for the remaining days (2 or so I think, but somebody who has passed their test more recent can confirm this) before doing your test on the fifth and final day.
