First off--TD Ameritrade is a fine place to invest--no real need to move to VG when you can trade VG ETFs for free.
Second, I would consider Rick Ferri's article on a "Flight-Path" approach to asset allocation. For people just starting out with investing, taking too much risk is a common mistake. He (and some others) recommend starting out with a bond-heavy allocation and then increase the stock allocation over time as you gain experience with market fluctuations. Nobody really knows what their risk tolerance is until they've experienced a bear market. http://www.forbes.com/sites/rickferri/2 ... llocation/
Third, the ideal starting point is always the "three fund portfolio", with a bond fund, a US total market fund, and an international fund. BND, VTI, and VEU are the three tickers you'd be interested in. If you are following Mr. Ferri's advice, a good starting point might be 60% in BND, 25% in VTI, and 15% in VEU. Over time as you add more money, you'd increase the allocations to VTI and VEU.