If I am liberal on social issues and conservative on economics issues, what party should I run for?

You're a green Libertarian, which is an unsolvable political paradox. You'll learn in school that your environmentalism CAN NOT be solved by market forces. You will have to compromise your economic principles or your ecological principles, you can't keep both. Only a communist concept of the ecology (the ecology is the property of all earthlings) will protect the human species from the damage done by profit-motivated businesses in a market economy (they externalize ecological costs to maximize their profits, it's a form of intergenerational fraud).