A search for Higgs-boson pair production in the final state is carried out with 3.2~ of proton-proton collision data collected at TeV with the ATLAS detector. The data are consistent with the estimated background and are used to set upper limits on the production cross section times branching ratio to for Kaluza-Klein gravitons in the context of the Randall--Sundrum model with a warped extra dimension and for a model with a narrow spin-0 resonance. In the context of the Randall--Sundrum model, upper limits of fb are obtained over a broad mass range of 600 and 3000 GeV, at the 95% confidence level. The production cross section times branching ratio for non-resonant Higgs-boson pairs is also constrained to be less than 1.22 pb.