If I start doing Vipassana now, how long will it take me to achieve Nirvana?

Call me an over-enthusiast but presently, the highest priority in my life is to achieve the object of Nirvana or moksha. By performing Vipassana, I want to achieve Nirvana and in this lifetime only. I'm prepared to do anything for it, even leave my current profession and staying as a monk if required. Trouble is, I just don't understand how exactly to go about meditation. I've read a few suttas but I just don't understand what to do while doing Vipassana meditation. In a 10-day Vipassana course I'd undergone, I'd done Anapana (breathfulness meditation) by keeping my mind on the entry and exit of breath at the nostrils. I've done this for several hours and I still do it sometimes. I also do mindfulness meditation sittings (by observing my thoughts impartially) for at least an hour in one sitting daily. Now, all these practices are great and take me into a calm and tranquil state of mind. But I don't seem to be getting anywhere towards my ultimate goal of Nirvana. Is there any way to know how long is it going to take me with this speed, or how do I increase the speed? Most importantly, **Is joining the sangha and practicing full-time monkhood the only way to achieve Nirvana?**