I hate to give you bad news, but typical parking bollards will likely offer minimal protection. I've seen vehicles that have hit these things going maybe 15-20 MPH and they get thrown 10'+. These are usually the kind that are screwed into some sort of base. Others I've seen break-off at the base (the kind with the base sunk below the surface). The reason this is important is because these folks aren't using their own car, thus they could careless about the disabling damage done to the vehicle. I think it mostly depends on the materials used and how they are constructed.
I live off a road with a curve and have been really looking for some large boulders or rectangle stones (the benches and/or protective barriers you see at parks in some areas). The larger ones do cost upwards of $1,000, but that is the kind of weight need to really stop a vehicle. The typical cement bollard will cause a lot of damage, and likely prevent a slower moving vehicle from continuing forward, but any momentum and the store front could still be compromised. You might want to check around for any free boulders or large blocks and use them if at all possible. Cement Jersey barriers should work, not sure about the plastic ones filled with water (the orange color could be painted over).
