Question
at first it was just a few bushes but now its all of them, they have big brown spots on the leafs ( it looks like they leaf is dying)

Is this a fungus of some sort and how do I get rid of it?
Thanks for you help in advance.

Answer
Brown spots on a rose leaf usually mean one of two things. The weather has been very hot and the dropletts of water on the leaves has magnified the sun and burned them. If this is the case, then the spots will not be on the edges of the leafs. The other reason could be a fungal disease called black spot but the leaves usually have literally black spots on them. Because you say that all of your roses are going this way, it suggests to me that it is a stress problem due to the weather. Rose diseases usually won't spread that way.
Just in case it is a rose disease, spraying with a fungicide called Funginex will cure it. Make sure the temperature is not over 75' when you spray or that will definately burn the foliage. Hope this helps.