For me personally that doesn't seem like a bad price for a custom made aluminum radiator - but ask my wife and you'll get a different answer!
If you have an older radiator that you believe is suspect, then I think you'll make some progress with a replacement. I'll also stress again to make sure you have good airflow through the radiator. Without it, you'll have trouble in SoCal traffic.
Really hope this works out for you. I know how maddening and frustrating a cooling problem can be. I've been there many times.
