New Hampshire uses the federal exchange, so you could go to healthcare.gov and sign up.
You said that you make an upper-class income, so you're probably not eligible for subsidies. That frees you up to buy health insurance from an insurance agent outside of the exchanges. Obamacare doesn't require you to buy from the exchange, it just requires you to have coverage.
Off-exchange insurance plans are still subject to the new regulations regarding how premiums are determined, what they must cover ("Essential Benefits," google it), etc. There's no harm in calling an insurance agent and getting a quote, then comparing the cost and coverage to what you can get on the exchanges. Just don't fall for a trap by picking the lowest-premium option -- look at all the costs including premiums, deductible, co-pays, coinsurance, and out-of-pocket max.
If you do buy from the exchange and are comfortable with a $10-20k deductible each year, you'll want to get a "Bronze" plan (lowest premiums, lowest coverage). But you won't find any $20k deductibles -- they don't exist. The limit for out-of-pocket max on Bronze plans is 12,700/year for families (half that for individuals). The limit for deductibles is the same, but since the Bronze plans are required to cover 60% of healthcare costs on average, the deductible will be lower, probably under $6000/year.
With all that being said, unless you had a qualifying event then you can't get health insurance until the next open enrollment period, like geekette said.
edit: Gin1984 is correct. 17 states run their own exchanges, 7 others have a partnership exchange with the federal gov't, and the rest let the feds run it entirely.