Sorry - no
two parts - database and theme
upgrade the database, it will not work with your existing theme
choose a theme from the new version and apply it to your upgraded database
you'll see what needs to be done re images, sliders, etc.
If you aren't in a position to do this yourself, definitely get some help
No matter what, do not upgrade in place! You need to separate the production and dev environments so you can test and tweak the results. Your site is not responsive and you need a responsive template.
I do hope the info helps but at this juncture, if you are still unsure of what to do, probably will save you lots of time, frustration, and definitely MONEY to get some professional help. NOP is still the affordable, extensible solution it has always been. But there is a reason we get certified to work on it - takes a bit of time for all this to make sense and some underlying skills to make it wo