Yes, it is true that reverb can help to glue tracks together in a whole. Do keep in mind that too much reverb is worse than too little.
Your question about the software is simple: you need an audio editor. I don't know much about video editing, but while they may have good audio tools, an audio editor is the way to go. Some (like MOTU Digital Performer) have integrated video support. In an editor like this, you can work on the audio with all the power a mixing console will give you.
