plugins for database creation

I have a website created with WordPress. It was written with code to create fields that link to other fields, and they all calculate to make an end result calculation. Can anyone either a) tell of a good plugin that would supplement the hard code or b) know of a good html editor/writer so I can fix some of the errors written by the previous designer? I have visions of the calculations being simple but I am lost once I have tables set up and try to link them to calculate. This is where I think a plugin would help. Any advice or am I SOL?