It'll help a bit, but it's not an end all. Get a 1farad.

Farad is a unit of measurement. A .5farad or one half farad is good for systems upto 500watts. A 1farad is usually good for systems upto 1000watts. So your over the 500 but under the 1000, so the 1farad is the good choice.

Get a name brand. I got a Rockford Fosgate one on ebay for $70shipped.