It's been a while since I had the opportunity to check in here. Where are you at in the process? You may be in surgery as I write. In that case, I wish you the very best and I'm confident that everything will turn out fine for you.
The more details I hear about your situation, the more it sounds like my own. My tumor was completely resected, as yours likely will be. Fortunately, they only removed about 10 % of my stomach, and besides the month or so of recovery post-surgery, I am eating full meals now like nothing ever happened. I was initially very scared because doctors would not rule out the possibility of having to remove more of my stomach once they were in there and looking around. If that is a concern of yours I wouldn't worry- it sounds like your tumor was noticed quite early.
I am coming up to the end of a year of Gleevec post-surgery with virtually no side effects. This a more of a preventative measure. The only problem is that I occasionally get nausea if I don't eat a full meal with my meds. As for the holistic route: I wouldn't rule out that holistic methods could assist you, but I would follow doctors orders and take Gleevec as well if recommended. This drug has proven to work effectively in a number of studies. Of course, I take common sense care of my body as well- running, eating well, sleep, no alcohol (a requirement for taking this medication).
Again, my blessings are with you during this stressful and difficult time. Please let me know the outcome of your surgery or where you are at in the process.