Repair Bathtub Holes

The Room in Question

Here it is. My hall bathroom. It's been gussied up with paint since we bought the place four years ago. However, the bath/shower stall is a mess.It's a cheapo, plastic and acrylic number. Trust me, it is much uglier in real life than it looks in this photo. And, alas, it's here to stay for at least a couple more years. Replacing it would be ridiculously expensive, so I'm opting for repairs that will hopefully lengthen its life.