I need help with an existing WordPress website for Stellar Turbochargers

The domain name is: www.stellarturbo.com

I already have the WordPress theme and need the following features:
- Bug fixes
- WooCommerce
- Google Analytics
- SEO
- Speed Optimization

The Website is currently quite slow and has a number of issues.

1. The checkout button is not working and throwing up an error.
2. the contact form is generating a lot of spam
3. I want to have google analytics integrated.