I had the wrong first link - I just edited it.
OK, that PX150 has no line out ports, except for headphone of which it has two of those.. It has USB out as well but if you are gigging and want to hook to other peoples sound systems you need an instrument with Balanced Stereo Line Out ports. Often this is a 1/4" port, designated TRS. You could also run into XLR out there someplace but you can get conversion cables for that from the 1/4" TRS to XLR. A piano more designated for stage use would be a better choice for you.. The least expensive of those that I know of is the Yamaha P105. It wouldn't be my first choice for what you want to do but it will fit your needs and they sound good, I've played one. The keys are weighted but I like a more firm feel than they offer personally.
Guitar Center should have one in stock. Kraft Music or Musicians Friend will for sure. Look for a discount coupon for this piano, they often come up at all these places, especially Musicians Friend and Guitar Center. Also plenty of You Tube videos out there on this.