I have, on occasion, actually counseled people to keep their gall bladders because their symptoms were infrequent and relatively mild. Mine, for five years, were neither. I suffered from severe pain, diarrhea, nausea, and just general crappy feeling off and on for months at a time. Sometimes I would be so nauseated that I couldn't bring myself to eat anything. I went from a size 14-16 to a size 10 in about 4 months because of my constant nausea. I had one unending gall bladder attack while living in Ireland that lasted three weeks solid: constant diarrhea and constant, unbearable pain. For me, having my hida scan finally show an abnormality was a relief. I went straight to a surgeon and got it out a week later.
It is quite probable that you will have diarrhea and/or acid reflux after the removal of your GB. You may continue to have nausea or feelings of fullness--or lack thereof (somedays I never feel full, no matter how much I eat)--although these, for me, are rare compared to the bad stomach feelings I had before. As Lil mentioned, I have medicine that I can take for the D, so I don't suffer from that very much. There was nothing that helped the D before I had my gall bladder removed and nothing that helped the pain and other symptoms.
So, while I'm not 100% fixed, I am better than I was. If you feel that you can live with the nausea, indigestion, pain, etc. then you're probably not bad-off enough to warrant going through surgery; you're likely to be the same afterwards as before. But, if you can't tolerate living like that anymore, then you are likely to be better for getting it out, because your symptoms should lessen.
I should point out that gall bladders don't repair themselves and usually get worse over time, so it's very likely that, even if you can tolerate your symptoms now, they will get worse to the point of unbearable later, which is why most doctors go ahead and take the gall bladder out.
Since you're likely to have to wait on your surgery for a little while longer, why not try a very low fat diet and see if that improves your symptoms any? I went on a low fat diet after I had my GB removed and it completely eliminated my D problem. Unfortunately, it made me terribly constipated, so I had to go off it--so no promises that the low-fat diet will help you any, but, you may buy yourself some time. Like I said, the gall bladder doesn't repair itself, so if you indulge in something fatty--like at the holidays--it will likely make you pay dealy for it, even though it may have been acting perfectly normal while you were on low fat. It will always be there, lurking, ready to punish you from any deviation in your diet. If the low-fat diet helps your symptoms, then it's up to you to decide if it's worth avoiding surgery to put up with the occasional gall bladder attack. If the diet doens't help your symptoms, then you're back to knowing that nothing short of surgery has any hope of relieving them, and deciding if you can live with them or if you will take your chances on getting the gall bladder out.