Backing up my phone

I need to back up m iPhone, because I hve many cherished memories and contacts that I need. But my phone hasnt been backed up in 22 weeks considering I had low storage. Also, I got urine in my phone so it overheated and some parts got burned and seems unrepairable. So I made an appointment with the Apple store, which is tomorrow and I will most likely get a new phone. My main problem here is that I have a Windows laptop, and I do not own a Mac. I do not know if its possible to use a Windows to bak up an iPhone. Remember that I cant turn on my phone. 😟 I also have another question; when I get a new phone, will all my mesages come to my new phone? I know this is a compicated question but please try and answer as best as you can. Thank you so much for your support.