Emmay...... I'm just so sorry to hear of your sister's added burden...
I did well for viseral mets on Navelbine/Herceptin. I am certain there are 'new' combinations that have proven better than the singles... Have you looked in the archives in bcmets.org?? That is where I have seen these newer combos. Here is an example of one:
ASCOâ€"Adding the investigational agent ixabepilone to capecitabine (Xeloda) resulted in a significant improvement in progression-free survival (PFS), compared with capecitabine alone, Linda Vahdat, MD, of Weill Cornell Medical College, New York, reported at the American Society of Clinical Oncology 2007 meeting (abstract 1006). The study included 752 patients with metastatic or locally advanced breast cancer resistant to anthracyclines and taxanes.
Larry Norton, MD, Deputy Physician-in-Chief for Breast Cancer Programs, Memorial Sloan-Kettering Cancer Center, told ONI, "I think this is one of the more interesting studies presented at ASCO this year. It appears that ixabepilone is helping a population of patients who are not responding to capecitabine."
And another:
ABSTRACT: Capecitabine and Mitomycin C Is an Effective Combination
for Anthracycline- and Taxane-Resistant Metastatic Breast Cancer [Oncology]
Fifty-three patients (median age 62 years) with
anthracycline- and taxane-resistant, metastatic breast cancer
... A median of 6 cycles were given ..with a
complete response observed in 2 patients (3.9%),
partial
response in 17 (33.3%) and stable disease in 19 (37.2%). Overall
response rate was 37.2% (95% CI, 24.0-50.5%), with a median duration
of 10.4 months.
Median time to progression was 8.1 months and median
survival was 17.4 months (1- and 2-year survival rates of 60 and 28%,
respectively).
Hope these examples will get you started. You do know that I have saved your sister's history for myself, right? 
Which is now helpful with my slowly progressing brain mets.
love & hugs to you and sis.
XOXOXOXOXOpatty