Need Help for Custom Sound System

[Icecoolwas]

Well Basically

I got a logitech x230
Infinity reference Amplifier (300w RMS)
12" Infinity subwoofer (250w RMS)
Ported Box
Headphone Splitters
RCA To Phono Cable
300W 12V 15A Computer Power Supply

What ive done is...
Got a Power supply, Used the 12v Rail to power an amplifier, Its being Powered by two 12v rails. Connected rca to phono, Headphone splitter, X230 goes into there (For mids) and into my PC.

My problem
My Amplifier Clips alot, and if i bridge my subwoofer after a loud Bang of 300WRMS the Power supply shuts down, and fails Until i restart it.

Researching it..
It looks like my Power supply, cannot "supply" enough power to the Amplifier.

Solving it
Getting a power supply that will Power more Amps (A) on a 12v Rail.

Solving problem
I need someone to reccomend me a Power Supply (Preffebly from ebay) Thats Cheap, Does about 25A+ on one 12v rail (I'm going to use two rails so it will be like 35A? I dont know how to add Amperage).

Thanks! I dont like a clipping amplifier, Most likely will die.

[Mike Anderson]

It could be an impedance mismatch. Are you sure the amp is appropriate for those speakers?