Ripple is actually not really new but still an interesting coin.

Their website lists several possible exchanges (https://ripple.com/xrp-portal/how-to-buy-xrp/). I have no strong opinion about which of these is most reliable. There are others (https://poloniex.com for example) where you can trade XRP/BTC, too, so if you already have an account at an exchange that you trust that might be the easiest way.