Ok so i know its bad but how bad..i have rust in my hose to the radiator

 

uhm, it could be pretty bad through time. Just dont be surprised if the car starts acting up.... how much rust or corrosion are we talking about?

 

probably had water in it for a while....

Just flush it good and depending on your climate run anywhere from a 70-30 water antifreeze, to a 60-40 water/antifreeze mix.

If there's no large rust flakes, but simply orangey/rusty liquid, you're probably fine. I'd suspect though that the water jackets in the keg would have some light pitting on them now which could in time lead to some major issues if the water/rust isn't flushed in favour of corrosion protecting anti-freeze.