Welcome aboard.
1) Depends how you look after her/him. If you abuse them, not long. If you maintain them, some girls here are 10yrs +.
2) I'd personally avoid eBay for Dolls. Go to a vendor. Cloud Climax, The Doll House, Lucid Toys, etc.
3) LucidToys are the only ones (I know of) that do offer a warehouse visit.