what are your thoughts

My wife Linda and I got the results from her third ultra-sound in 6 months for her liver mets. The report says that there has been no change, consistent with extensive heptic metastases (75% of liver mets). She is on Navilbine + herceptine, feels fine however we were disappointed that over 6 months there has been no tumor shrinkage, just stable disease. We have brought this up before and the doctors say: if it works, don't change (the chemo). We are still in the position of waiting until the current regime stops working before they will change the chemo. Given the extensiveness of the mets, I'm afraid we are only going to have 1 shot at a second regime; sort of a do-or-die (ie, by the time we find-out #2 doesn't work it will be too late). We have a consult in Toronto next week and I would like to have a game plan together, even if it is accepting the current one. Any comments or opinions appreciated.
Al