I got around this great expense by making cilantro oil during the summer months and freezing it in baggies. I defrost the baggy for the time it takes me to cut up some tomatoes and onions, and voila, the addition of that cilantro oil does wonder to my make-shift winter pico-de-gallo.
Come spring, cilantro, and other herbs, in addition to green onions, even cherry tomatoes will have their patio space and my problems are solved. A patio or deck provides wonderful ambient for growing difficult plants. You can move them against the house at opportune times of the day for more shelter; or, you can cover them with plastics at night and provide each pot with a particular shelter.
The more you harvest, btw, the more the plant grows. You are fed on demand this way!
I'm looking forward to these opportunities.