Onc. denies Herceptin forever bcause of low MUGA

As you all know from my previous post that I had my recent MUGA which showed ejection fraction of 44% (3months ago it was 56%).
I had an appointment with my oncologist today to discuss the future action. He says he is not going to prescribe me Herceptin forever (in nonmetastatic conditions) even if my Heart function improves and the EF shows more than 50%. I begged him to redo my MUGA after a month or two and he denies saying that I already had 6months of Herceptin and it should be enough. He says the heart strengthening medication is just going to put a bandage around the problem and it doesn't really strengthen the heart. He wants to repeat the MUGA immediatly to rule out any false readings. If it comes same he will never give me Herceptin.
I really want to finish my one year adjuvant Herceptin so that atleast I will get the benifit mentioned in the clinical trials.

I am on Herceptin alone since March 05 after finishing my AC + Taxol. I am stage 3b with supraclavicular node involvment.

Really confused and stressed about not getting the drug. Please help me if you have any suggestions.

Thanks,
Julie