Change Color of a part of the picture. How?

[erde]

Hi
I really looking for a solution how can I change the color of a part of a picture.
In my case it's a pharmacy sign (see attachment). I want to change the color of the white Part (snake&scale) into a sort of brown (#bcb29d).
The green cross I want to change into red.

I only managed (not even that perfectly) with hue. But I cannot choose exactly the colors I want. I manage with the color/select tool to select the region I want to change but then
I don't know how to move on.

Please I'd appreciate any help.

Ernst