Anywhere from around $75 to $150 but you won't know for sure unless you ask a Koodo shop or a third party vendor who repairs cell phones.
An alternative is looking into upgrading your phone. If you have around the same amount of -Tab as it would cost to repair your phone, you could always grab a Nexus 4 for free or Galaxy S III for $50 on the medium Tab.
Or if you wait a bit longer, the Nexus 5 will be on Koodo shortly. Pricing hasn't been announced yet.