What software would you recommend I use to format my 100+ page master's thesis?

It is currently in Microsoft Word, and looks hideous because there are so many images that don't stay in the right place despite how many times I tell them not to. Wrapping text as tight, etc., and resizing doesn't seem to make a difference when Word is intent on randomly sending the image down a page.

Would Adobe Illustrator be good at what I'm looking for? How is it with handeling loads of text? I recall that Google had some sort of PDF book maker, but I can't remember what it's called. I don't want to spend much money on this.

Thank you!!!