Multitronic Failure? - 143 S-Line

After looking for a good while, I finally bought an immaculate 10 plate S-line about 5 weeks back.....
All was great up until this past week, I started hearing a very small whine at about 3k now and again, noticed when starting off slowly on a steep hill I was experiencing some slight judder and there was hesitation to drop into second sometimes (it would also not engage second in manual unless at over 2800).

Skip to this morning when the misses calls me to say she's broken down and is on the hard shoulder with no drive whatsoever, showing fault on dash 'Gearbox Malfunction, continue to drive'. I've had it towed to the house and am now in a bit of a loss as to what to do - does anyone know of anyone reputable who can have a look (I'm in the Wrexham area)

To top it off my warranty only covers me up to £500 (RAC), this wasn't explained to me on purchase (nothing was signed with regards to RAC docs and I was told these would be sent in the post, however It's written on the invoice '3 months Platinum Warranty', although the paperwork that I've now received says Gold). Legal experts feel free to confirm I'm screwed here....

Any help or possible ideas on diagnosis MUCH appreciated.

Thanks

Thanks for the replies, the car has done 98,000 with full Audi history and two multitronic oil changes.
With regards to the warranties, I believe the detail on the invoice is a mistake on the garage's part as the Platinum Warranty only covers vehicles under 75,000 whereas the Gold is 100,000. I had to chase the seller for the information a couple of times, they were probably aware of it.

The Gold Warranty does cover all Gearbox failures so there's no problem there, the issue is the £500 limit wasn't relayed to me at sale, if I'd have known this I wouldn't have parted 10K (In hindsight, a mistake on my part for not asking I suppose). The dealer is a small, independent local dealer (RAC approved apparently), I'll keep them anonymous for the time being whilst it pans out.

The error is constant on the dash when ignition is on, it's strange - no real warning of failure, it's just as if it's jumped into neutral.

Having a quick search it seems like there are some pretty reputable guys over at Bristol Gearbox Centre who'll fit a reconditioned unit for under 2k (worst case scenario), need it back on the road ASAP but not willing to part any cash unless I've no other option :-(