If you call those numbers on the flyer, you are a special kind of idiot. A very low fee will be quoted to get someone there. She will then quote you 500-1000 for anything resembling fun. and it won't be fun, it will be a 10-15 minute rip-off job.
Stick to eccie.net, lvfever.com/theotherboard.com, and TER for solid vegas info and reviews. Stick to indys and be prepared to spend 400 to 600 an hour. Even EROS has a bunch of bait and switch ads. 100 proof is the only agency worth using, the rest of them are rip-off joints.
You can also play the casino girl game, basically every major strip hotel lobby bar or lounge will have working girls in it from 7 or 8 pm to 3 am or later. BE very careful and don't get too drunk, or you will find yourself ripped off. Stay off the street, you can get mugged, busted or worse. Prostitution is NOT legal in Vegas, only in certain counties in Nevada. The cops usually leave the tourists alone, but be smart.
If you really want to, a cabbie will take you to Pahrump and one of the legal ranches, but it will run you at least a grand for the cab and the girl when you get there. You can also try your luck getting takeout from a dancer at the Spearmint Rhino, OG or any of the other larger clubs, again it will be pricey.