Stretching part of an image to fit a border

So, I wanted to put another image on top of one that I had (sorta like re-texturing) but the image is more slim than I need it and i'm not sure how to stretch it to be able to make it fit.

I'm trying to get the aqua blue on the left of the image to stretch and replace the light grey lines  and on the right of the image, trying to get it to fill up the whole part with the writing on it.

so basically I need to stretch the coloured image to fit onto the grey underneath but stopping at the red on the left, how do i do this?