Can I Take Builder to Court Again for New Problem?

My house was finished (new construction) and purchased 3/31/2006. I had several problems with the construction and the builder did not fix any of them for 1.5 years. Finally, I took him to court and won a settlement to have the repairs done myself. Now, my water main is leaking through a wall. It is still within the four year period allowed for plumbing, foundation, walls, water leakage, etc by California Code, section 896.

QUESTION ONE: Since I already won a settlement for construction related issues, can I still take him back to court for a settlement on this newly arisen issue, or does everything have to be settled in one case--even though this problem had not surfaced yet, at the time?

QUESTION TWO: Can a relative do the repair work if he matches the price of the lowest estimate from other companies? I would rather have someone I know I can trust do the work.

(It was obviously past the point of having the builder do the repairs a long time ago--he even threatened me before I took him to court the last time).