The expo is held at the Radisson Hotel in Manchester (603 206-4209). You can also try their online reservations site at www.radisson.com/manchesternh The hotel is ok with discreetly contained live animals. They do put aside a discounted block of rooms for the reptile expo- currently $129/night, use code REP927.
Be sure to reserve your room at least 30 days ahead of time to get this rate, as the Radisson often sells out on weekends.
The Hilton Garden Inn is only a mile away- their number is: 603-669-2222
Avoid the Sheraton 4 Points- they used to be pet friendly, but have recently been turning away anyone with reptiles.