Dear,
I can help you, I am an expert in computer security and I am currently working on perimeter security.
I can perform the following tests on your site.
Manual test
Automatic test (tools such as acuntix, burp)
Static code test (hp fortify)
Stress test
With all those tests, plus the ones that you indicate could make sure that your site is safe, I can also implement a WAF for the site.
regards