Question

Exterior metal staircase has bad rust.
It has ornate railings on one side but the staircase itself is a function fire escape kind. We had it repainted a couple of years back but I've just started noticing that some of the railings are getting really rusty and some bits, where they curl round, have broken off. There's a small hole at the back of one of the stairs and on the side and some other bad rusty patches.

Probably worse is that the stairs come up to a little landing outside our first floor front door. Where it rests on the wall, the rust is bad and it has flaked and broken in places. I think it needs more help than a bit of sanding and a two coats of Hammerite, it looks like it's deteriorating quite badly. But we can't afford to replaced it so is there anything I can do to fill the more damaged areas first? Thanks