I worked with a company as a web developer intern for 5 months and they use typo3 so I'm familiar with it.
I have a very good understanding in the functionality of typo3 and i know CSS, Html and can modify JavaScript codes or create simple ones.
The side bar can be hidden by a simple CSS code, i"m not sure about what you want regarding the menu but it looks simple.
i will do my best to help you fix and improve your website, i think i have what it takes to do that.
Thank you!