I'm with FT in that BJ's almost never make me bust (only two girls have proven me different gifted with major DSL's).
As far as what to do, I (and Alek wrote about this too) prefer to get dome --> eat her pussy --> fuck. This way your cock has some time to rest after exploring her first orfice, she's nice and ready for re-entry, and then you both enjoy the sex lubed up and not ending prematurely.
One way I love to do this (and they do too) is have them blow you with you standing up, them on both knees until you've had enough, lift them up while kissing them/their neck, lay them down in bed (or whatever usable surface) and start with the tongue action. Works for missionary and doggy style with how you arrange them so you can just put your dick when they're ready.
If you want to see this girl again, be absolutely sure you get to dick-in-vag sex if at all possible.
A girl can (and occasionally will) blow you and still never see you again. But the odds of a girl wanting to see you again after taking your dick in her pussy skyrocket way up in your favor. So if this is the first time you two are getting intimate, you might hold your load and save it for when you are thrusting inside her. This is assuming you care about seeing her again of course.
If this is not your first time having sex with her, then do whatever you feel like! Do note that you need to be giving a woman orgasms at least semi-regularly if you want her to fall for you and keep seeing you. Women are not fond of selfish lovers who always want to cum before they are able to do so as well.
There's no clean cut "3 times a week" definition of "semi-regular".
You want her having orgasms as frequently as possible. If she's not cumming all the time yet, no biggie. Do your best to make sure a girl cums at least once every time you have sex, and train your dick on how to do so.
Hue has the right idea. I aim for at least one orgasm every time we have sex. That usually guarantees optimal happiness for the girl.
(NOTE: Just because I "aim" for it doesn't mean it always happens. I'd say I usually end up somewhere in like the 80-90% range of the girl I'm with having an orgasm at least once every time we have sex. But there are times where I'm just way too horny and end up finishing early, or there are times where something unusual happens and I just can't get her there. But as long as she feels like you're a man that aims to please [and often does], then she's going to be thrilled with you)