[H3O+] and [OH-].......
Sulfuric acid is a strong acid, but only for the first H+ which comes off. The remaining HSO4^- ion is a weak acid and its dissociation is negligible in the presence of 0.0055M H+. Therefore, the [H+] of a 0.0055M solution of H2SO4 is 0.0055M.
Kw = [H+][OH-] = 1.00x10^-14 .............. at about 25C
[OH-] = Kw / [H+] = 1.00x10^-14 / 0.0055 = 1.8x10^-12
You may not have been exposed to acid/base equilibria, and know little about strong and weak acids and chemical equilibria. Therefore, your teacher may be expecting you to assume that H2SO4 produces two H+ for each molecule. In which case, double the H+ concentration and cut the OH- concentration in half.
Calcium hydroxide is a strong base, but not a very soluble base. Therefore, what little Ca(OH)2 dissolves will completely ionize. A quick check shows that a saturated solution of Ca(OH)2 at 20C has a concentration of 0.0233M. Therefore, you 0.011M solution is viable.
Ca(OH)2(aq) --> Ca2+ + 2OH-
[OH-] = 0.022M
Kw = [H+][OH-] = 1.00x10^-14
[H+] = 1.00x10^-14 / 0.022 = 4.5x10^-13M