Confused about Tykerb

[Rupali]

Hi all,
Whenever I am confused I always come here and try to get answers. And thats what I am doing today.
This time the confusion is about Tykerb.

So let me first explain my diagnosis and treatment.
December 2004 found a lump in right breast
Right breast mastectomy: December 2004.
Stage 3C with 12 out od 22 nodes postive. 9cm lump Grade 3, ER+, PR+ (10%), her2+++
4 DD AC, 4DD Taxol
2 years of Herception every 3 weeks (now finished)
Tamoxifen and zoladex started in 2005 when my periods returned

SO I am done with Herceptin now and soon will be switching to AI with zoladex.
Now comes the new drug Tykerb.
My husband does his research and finds that Tykerb is a good medicine and can cross blood brain barrier.
I have 2 oncs, one is at a big cancer research center in Boston and the other is a community oncologist.
What I am confused is that is Tykerb something I should take now or keep it as an ammunition in case I need it at a later time.
If I was to take Tykerb now then would it be with Xeloda or tykerb alone. The community onc said there is no need of xeloda and she would not agree for it.

Is it a good idea to just take tykerb for 3-6 months?

My EF is down to 45-50% right now and is that sufficient to start tykerb?

Does anyone know how cardiotoxic is tykerb?

Please answer, I am all confused.