Lotta good advice above, but, IMHO (and I am just back from a "free" miles redemption trip in biz which included BKK, for what it's worth) I would be looking at getting some real miles from credit card bonuses and flying biz or first for the cost of taxes only (around a 100 bucks or so).
Initially, take a look at this thread
http://www.flyertalk.com/forum/miles...t-2-first.html
If you can work the three apps discussed you should get 225K AA miles in a few months which will certainly get you to BKK in more comfort than going coach.
There are many other good card app bonuses to be found on FT. But the 3 AA is a very good start.
Can't believe I used to fly coach and pay for it! Thanks FTers for sharing.