ok, your moles for HCl is right but its (OH)2 in Ba(OH)2 so its 0.005 x 2 = 0.01.
Then work out how many moles of H+ are present after all the OH are neutralised (that's just the difference between them) which is 0.00875.
Then work out the concentration of that H+ by dividing 0.00875 by 0.025 +...