help with error on my store page

Your theme is version 1.3.0 but the current version is 1.3.4. Your WooCommerce is 2.1.9 but the current version is 2.2.8. Your WordPress is 3.9.3 but the current version is 4.0.1. These separate elements need to be up-to-date and in sync so they co-operate with each other.

Take a backup before updating.

Thank you, just upgrade and backup? sorry to ask this but how do I back up?

https://codex.www.ads-software.com/WordPress_Backups

There are plugins which can help with the task.

should I be installing plugins if that is what is causing my issue in the first place?
Thanks
Denise

Yes, they can be deactivated in the unlikely case that they make things worse.