[Gimp-user] Insert Image- Not merge

[kevspass <forums gimpusers com>]

Hi All,
I have just started using Gimp and see that it can do almost anything(!?)
However, can someone please tell me how to do the following?

I have a very long horizontal image (single line of music notation). I need to
space all the bar lines up at equal distances apart. I am using the grid to
guide me.

I therefore need to 'stretch' part of the image by copying a section and pasting
it at another point. However, I can only seem to get it to merge the copied
section over the top.

I want to 'cut' the main image and insert the piece thus making the width if the
entire image longer.
Is this possible?

Or is there a way to select a cross section (from top to bottom) and stretch it
sideways- also moving the rest of the image along?

I hope that all makes sense . 
Any advice is appreciated.

-- 
kevspass (via www.gimpusers.com/forums)