Front suspension something broke!

Hi I have a problem with my front suspension, went down a pot hole bang drove home no real issues and found the nearside is sitting lower the the offside.

I haven't taken the wheel off yet (the weather has been awful) but I suspect it could be a broken coil spring, and that's the problem really you see the car has been fitted with hard sports type shocks and springs and I not sure what they are?
I always intended to change to a soft ride set so I suspect now would be as good a time as any, I would also like to get rid of the Oz wheels and replace them with regular wheels. Not because I don't like them but because there are more potholes than tarmac of most of the roads around here.

Is it a big job to change the shocks and springs and what should I get? What do you thing of perhaps getting a second hand set (so long as they are clean and dry, no leaks)
I need the car so I would normally get the local garage to do it for me and I going to have to work outside as there is not enough room to work on it,.

Any suggestions or advice would be great?

Could be a broken spring, but went they go you know about it. When you get the wheel off, have a look at the track control arm ( wish bone) they are known to corrode and it may be that has bent.