integrated voip api

hello everyone i have website in which i just need to integrated voip api so that by click to call function can work my website is like [login to view URL] if you see this website when user click on astrology online call button then by toll free number one call goes to astro mobile and one to user that only function i need in my website i already take voip service if anyone have experience in it then can do it easily its just 1hr job so if you cant do in max. 2hr then dnt bid on it thanks