Don't bother. The opportunity cost of going to school is too high. Experience and knowledge is more important.
There has been a lot of debate on the programmers section of this site. There's generally two opinons. One is that they are great, the more papers you have to your name the more attractive you are to your employers. The second is that they are a waste of time, and are a signal of someone who wants to 'get the job and cruise'. I've seen both of these attitudes. Generally, the more nimble startups and very focused shops don't pay any attention to certification in my experience, whereas large enterprise will appreciate them (though to varying extent).
As long as you have some university degree, 10 years into your career it won't matter what the field was. If you can talk about things you've done, things you know, and things you can contribute, that will matter much more.
Don't get me wrong, it would be IDEAL for you to have a comp sci degree if you want to be a developer, but now that you don't, it's better to invest your time doing other things.
What to do instead:
1) Learn new/tomorrow's frameworks and technologies.
2) Read books/learn general theory. Go through data structures, algorithms, design patterns, etc.
3) Participate in open source / build something of your own. Put that experience on your resume.
The things above will serve you much better than sinking 3-4 years of your life and un-earned income into schooling. IMHO you will honestly learn more. It might also do more for you than sitting through power-point slides of online accrediations.
Finally, there' something to be said for self-taught developers. When you have a guy from general arts that did a lot of work to go into programming you know this person is passionate and interested in it. You also know that they were/are willing to learn and aren't 'done' with their professional development (IMHO developers who are 'done' learning should get out of the biz).