Where can I find the correct POH for my Cessna 152?
Strictly speaking the POH/AFM is specific to your airframe as it generally contains the weight and balance information which will be unique to your airframe as it is equipped. Thus you should always reference the POH that is in the plane for the most accurate source of information. 

For example here is a nice scanned PDF of a POH for a C152. You should confirm that the numbers match those in the POH for the airframe. As long as they do you can use it for reference. The POH does not need to match for the specific year but it does need to match for the given aircraft configuration and setup in regards to the engine and performance data as well as any data related to things like extended range tanks etc.