"How long will my 06' Lexus IS250 with 132K miles last?"
^^ Nobody can answer this for you because you and I both don't know.
"Could it last another 100K miles?"
^^ Why not? I am sure it can!
As long as you follow your Lexus's maintenance schedule with the appropriate mileage then yes, it can. Doing oil change is one thing but focusing on other areas such as all your engine fluids (brake, differential, coolant, power steering), belts, timing chains, spark plugs, tire balance & alignment, brake pads and rotors serviced, and etc will help your car run strong for many miles. More maintenance work see link below.
Link:
http://drivers.lexus.com/lexusdrivers/info/my-lexus/service/maintenance-schedule.do
http://www.lexus.com/pdf/service/MY11_Lexus_IS_250_IS_250C_WSG.pdf