|You can stimulater her clitorally to te point of orgasm during sex, it just takes a little bit of dexterity - or she can do it herself.
As far as the vaginal orgasm... It is very possible for many women, however some cannot. Still, before signing off on the "she can't do it" card, there are things you can try.
You said she feels like she has to pee? Good! That means you're hitting the right spot. You just have to keep it up. Make sure she knows that this sensation is perfectly normal, and that she needs to relaxy down there, instead of tighten up - I know I get too tense to vaginally orgasm!
Maybe put down a towel or two, so she won't be as frightened, since from her point of view it may feell like she's going to pee everywhere!