Re: Quick advice needed (Wingmirror, tyres, rear windscreen)
Welcome to AO.
Tyres, don't know where you are, but I always order mine online and get a local place to fit them far cheaper IMHO. Just ordered some yesterday they arrived today at noon.
Not a fail point as long as its present and secure. As to fixing, you need to find out what is broken, I suspect the circular metal piece inside, if so this is too difficult to fix. Just get a replacement on ebay, about £40-60.
Windscreen, call your insurance co. , they will give you the relevant numbers to call.