Your best bet is probably a set of Edelbrock Performer RPM heads. Jeg's lists them for $980 a pair. They have 70cc combustion chambers which will work with your current set up. That's the cheapest I know of that will work with your engine and boost your performance.
As far as it being worth the expense, that's a fairly subjective question. The RPM Heads will raise your compresion ratio about 1/2 a point which is always better and since they are Al you can keep running 87 octane. They will flow a lot better than the 882's so you should notice a significant difference in the power.
Will the extra power to be worth $980? That's a question I can't answer. It depends on how deep your pockets are and how bad is your need for speed.