Investing in a bankroll with a new site and new user in Bitcointalk is kinda hard to do. At First it will be hard to get investors but there are many ways how to get trust from investors. What you need to do first is make your site known by many, Create events and escrow the prizes that way they will trust your events and many people will play your site and soon you'll get your investors.
Yes,its really very hard to trust for the very first time specially on newbie accounts which claim they do have gambling sites and we all know there are lots of new gambling sites turns out to be scam and when we are talking about trust its hard to build if the actions have been made arent justifiable.
That's why I would be good if you set a signature campaign with a trusted manager and set the minimum amount of investment quite low (0.01). If the site is really as different as you say it is from other sites, perhaps there is a chance yours will become popular. But in general I guess now isn't the best time to create a new casinos. There too many out there already. Perhaps it is better for you to invest the money into something like Crypto-Games. It is less risky, at least.
When we speak about promotions or exposure then signature campaigns would be suited on this one but its not guaranteed that you could able to get huge numbers of gamblers but still a good way on promoting the site and the most common one being used here. Anyone could make their own new gambling site but i would like to suggest to create a something new game that is unique from others. If other found out that your site is doing great then potential investors will surely come in.