Don't stay in Pomona! Run, run far away. I haven't been to that area is over 10 years but last I went, it was BAD, BAD, BAD.
Maybe you can stay in Corona Hills or Diamond Bar ( I grew up in Diamond Bar, last I went 8 years it was still a nice affulent town). Brea is nice, nice shopping. There is a mall/outlet called Ontario Mills not to far from Pomona but not all of Ontario is safe either...