Crowdfunding is a great method to build a customer base, get feedback on the product and provides a targeted marketing channel. In your case, it appears the product is already available so I do not see the appeal/anticipation of the crowd in this case. I agree with the earlier experts here that this may not be your best avenue and you may end up expending more resources for limited gain.

You require a great pitch video/message for your audience that is simple, engaging and would ignite interest. Throughout the effort you will have to constantly maintain contact and update your supporters and backers. You will need a dedicated, pre-seeded general and social media strategy and have prizes or specials through the campaign to keep interest going. Not all campaigns strike gold from day one and others have an ebb and flow as interest wanes and returns so you will need a dedicated marketing team setup months ahead of time working prior to the launch.