Yep - lack of a gall bladder could definately contribute. The gall bladder produces bile salts, which help to chelate bile acids and enable the liver to clear them out of your blood. (or something like that - it's been 17 months since I last had to think about this stuff!)
At this stage, you really don't need to worry unduly about your baby - OC doesn't normally become dangerous for the baby until 37 weeks, and by then you should be being monitored (if it is OC)
You will probably be offered Ursodeoxycholic acid, which ususally markedly reduces AST/ALT levels, and bile acids. It can also have an effect on your itching. Make sure they are also monitoring your Vitamin K levels and giving you tablets/injections to top up if necessary. (Vit K is fat soluble, and because liver isn't processing fats you can have a deficiency, which can cause problems with blood not clotting)
You will probably also be recommended lots of CTG monitoring, but, IMHO, this is worthless - it only tells you that your baby is OK whislt you are strapped to the monitor and has no predictive capability. So accept it if you want regular reassurance, but if it's stressful to get to hospital and lie down for and hour 3 times a week then don't feel you have to. Of more use are weekly dopplers - ultrasound scans of the blood flow through the umbilical cord (some consultants believe problems for the baby are caused by sluggish blood flow) and even better a ductous venousis ultrasound scan - this measures the flow of blood through the babies heart.
Which hospital are you at? You're in London aren't you?
For the itching, as you've found coolness is the only thing that helps. I used to go to bed with champagne bottle coolers wrapped around my feet. I also found a fan helped at night (or dh blowing on my feet ), and a minty cream - I used a peppermint leg gel from the body shop, or you can get normal aqueous cream with 5% menthol in it (from chemists but you'll need a prescription) - you stink, but the evaporation of the menthol has a lovely cooling effect.