Righto mate.... lets see if we can sort this mess!
Oh btw - I looked your car up on CAPS.... It was originally a manual
And here's some more bad news...That bolt that has sheared the captive nut off is part of the subframe. That bolts is one of 6 bolts that hooks the subframe to car - that includes the 2 bolts that hold that big ass bush to the car, they also hold the subframe to the chassis. In order to get it out, we have to drop the front to rear cross member out, and we have to pull the steering rack out
We really need to get it to a shop & onto a hoist - here's the pic:
Red circles indicate the other mount spots to the subframe, arrow is where the busted bolt is.
The good news is, those lower ball joints are a loose fit type of joint. They have to be as they swivel with the steering, hence we dont need to change them.
The steering rack arm we need is a screw fit, part number MR279969. If anyone has one of these spare *looks at dstocks

* let Jono know.
Also available thru Camskill:
http://www.camskill.co.uk/products.php? ... b0s583p671
You also need the boots that cover the arm:
http://www.camskill.co.uk/products.php? ... 0s583p1331
I would also suggest you get some droplinks:
http://www.camskill.co.uk/products.php?plid=m3b0s10p151
The only thing that leaves us with is the stepper motor, of which I'll lend you my spart to see if it fixes the idle issue, then the alternator issue... sounds like it needs reco-ing.