Radeon 5450 hdmi analog speakers

Hi, I just installed a Sapphire Radeon 5450, which has an HDMI port along with a VGA and DVI ones.
My display is a Samsung Syncmaster B1740 which doesn't have an HDMI port, only a DVI one.
I connected my monitor to the Radeon through a DVI-to-HDMI cable.
I have simple external speakers with the usual 3.5mm audio jack that is connected to the motherboard's audio input jack, as the radeon doesn't have any 3.5mm audio port.
Now, at the expense of sounding like a retarded bafoon, I want to know if there is any way I can get HDMI audio with my current speakers?
The device manager in Windows 7 shows that the AMD HDMI AUDIO is ''Not plugged in''. The Realtek speakers are activated and running.

Is there like an HDMI connecter/cable available that would allow me to connect my speakers to the Radeon's HDMI slot? (I can use a DVI cable to connect my monitor)?
Is there ANY other option besides buying a monitor with HDMI ports.

Thank you for your feedback in advance.