Use Bluetooth Headphones with Phone and Old Laptop I am wondering if there is a way for me to play audio that is coming into the headphone jack on my phone out of my phone's bluetooth. I have bluetooth headphones that do not work with my old laptop but I could easily plug a male-male headphone cable from my computer into my phone. If I did this is there a way to make the sound coming out of my laptop be played over my phone's bluetooth?

Alternative solutions are also encouraged, however I thought this one was the most plausible.
I am not sure this will exactly fulfil your requirements. But i think USB Bluetooth Adapter Dongle would enable Bluetooth connectivity to your old laptop and you can play directly via laptop. 

When you have easy access to your Bluetooth headphone from mobile then why don't you transfer audio files into your phone :-)

What I have understood from your question is :