To maximize employability you'd want a degree from a reputable 4-year brick-and-mortar university. On the other hand that's probably also the most costly and time-consuming option. Some ideas in no particular order:
1. Go back to the university where you earned your English degree. It hasn't been that long since you graduated, so you may be able to apply your existing credits to a C.S. or Math degree. That might allow you to get the second degree in as little as two years instead of four. If there are any required classes for the 2nd degree that can be taken elsewhere (e.g. a junior college) and transferred in then doing so can lower your total cost.
2. Go through one of those "Code Academy" places. This still costs money but takes way less time. It also offers less in terms of employability, but it's better than nothing.
3. Teach yourself some of the basics of C.S. Data structures, algorithmic complexity, discrete math, etc. Possibly through some online courses. Then self-teach yourself Objective-C+iOS or Java+Android and create some sort of app. Put it in the store. Interview for junior level app developer positions. If you have an app in the store and can talk intelligently about how it's designed (and why you chose to design it in that particular way instead of various other alternatives) then many employers will overlook your lack of formal C.S. education. Even if your first software dev. job is shitty, the point is to get your foot in the door. Once you have a dev. job on your resume it becomes that much easier to get other (better) dev jobs, because employers will no longer see you as someone with no experience in the field.
4. If you can stomach it, the military actually isn't a bad deal. Last I checked they were offering an abbreviated 2-year full-time commitment (with a longer period of national guard duty). At the end you get a sort of "half" version of the G.I. bill. More importantly (at least, it would be if you were younger), being honorably discharged from the service severs the link between you and your parents when it comes to applying for financial aid. Their income and savings is no longer taken into account when calculating your "need".