Or better yet, create a virtual machine (using Virtualbox for example) with a Linux installation and install everything there, this way it won't affect your computer and you can replicate / replace / create different versions of the virtual image anytime.
Can I install XAMP with the AMP install I have now
or do I have to remove one?
You will have a conflict there because XAMP will install Apache, MySQL and PHP in its own path and will not respect what's being installed already. It is likely that since you already have a versiion of Apache running, it will use port 8080 instead of 80 which will likely be occupied by the first installation.
Before asking, do a search... if you don't find the answer, then ask The purpose of this forum is to help others in the community, that's why it's called Sitepoint and not Linkpoint. SP Guidelines - No fluff.