Pictures really help us - or a sketch of the current floor plan uploaded as jpg - bathroom plumbing is expensive to move but sounds like you might need new fixtures and finishes. White is clean in a bath and always right. you can save by using a painted beadboard wainscotting. A row of hooks at kid height can be really terrific for robes, bags of bath toys, etc.
Go to a website like plumbingdirect to see the range of features. Set a budget - maybe you just need new valves, fixtures, tile and to paint what is left - open shelves with baskets are another great solution for kids - if you have a storage w a door, taking the door off can sometimes help. Give us some info and we can help more.

This is the only picture I can find online of it - I'll try to take more tonight. Truthfully, I think the whole thing needs to be gutted. It looks outdated.