Hi, happy to jump on a call to advise with the setup of lead capture & nurturing through drip email sequences. Your man for advice on integrations would be Denis from Integration Agent denis@integrationagent.com

I don't think you need a CRM immediately, but you do need to implement a drip email sequence that educates, nurtures and qualifies leads based on behaviour. I'd recommend taking a look at Drip - I wrote a post on why I moved to them from Mailchimp http://www.richardpatey.com/email-marketing-automation-leaving-mailchimp-drip/

I'd recommend checking out https://www.pipedrive.com - great drag and drop pipeline view (no affiliate or relationship with the company).