Had to replace my laptop keyboard as pesky ds2 had pulled loads of keys off. Got a bargainous one off Ebay from Hong Kong but some of the keys are different. Have sussed them out but can't find a pound sign. There is a $ above the 4.
I used to have that problem with my Japanese keyboards. Basically it wasn't worth the hassle of trying to get a pound sign for emails, forum posts etc, but in documents, you can use the 'insert symbol' thing in Word (presumably similar in other programs) which calls up a list of all sorts of non-alphabetic symbols, and you just pick the pound sign. Bit complicated though. How often do you actually need to use it?
Mine has the same keys as yours to the right of the L, but then one more key - the enter key is cut away a bit to accommodate it.
Make a list on a post-it note of the Alt codes for those that are missing or not where they say they are (I have one with the codes for things like euro, upside-down question mark, copyright, trademark - not that I use them often, but when I do I want them now!)
PLB- sometimes when my PC runs a bit low on memory (because I have 200 tabs open in Firefox and a pile of other programs running) the " and @ swap and I know I have to shut down some items as FF has stopped using the UK keyboard layout. Incidentally - it is only Firefox that swaps the keys over!
I think your machine has been set to UK keyboard (hence pressing shift-2 gives quote marks) but the symbols on it are the US layout.
One option would be to get a cheap UK USB keyboard and plug that in.
Another option (from times when I am using LogMeIn to remore control a client's PC and the keyboard is stuck) is to use the on-screen keyboard (comes under Accessories, Accessibility tools) which should show the correct keys for you.