First of all, we don't know whether or not the SCC will actually strike down the bawdy house and avails laws (the lower courts have done so, but we can't predict how the SCC will rule on this).
Second, it is one thing for the Conservatives to issue a policy statement condemning the purchase and sale of sex, it is quite another to actually bring forth legislation to further criminalize prostitution and face scrutiny for doing so (not to mention that any such new law will have the potential to face further court challenges from the same people who brought forth the court case in the Bedford decision). Furthermore, the Harper government has generally refrained from diving head deep on social issues for fear of being tainted with the charge of having a "hidden" agenda -- occasionally he's thrown a bone by, for example, cancelling the long-form census, but that's about as far as he's gone.
What I suspect will more likely occur will be one of the following, assuming the SCC actually does strike down the bawdy house laws:
(1) Harper and others within his government will issue a public statement strongly condemning the SCC decision, point to their own policy statement, but otherwise do nothing further. Not unlike their stance on same-sex marriage.
(2) Harper and his government will invoke the Notwithstanding Clause to effectively nullify the SCC decision and continue to keep the current bawdy house and avails laws in the books, so to speak (i.e. the current status quo). Taking this approach will spare the government from actually crafting any new legislation while still being consistent with their stated opposition of legalizing prostitution.