IMO, it's the old adage-
You can have it good, fast or cheap - PICK TWO.
So if you're shopping around for tickets - coupla things to consider:
1. just because she got a pink slip - it doesn't guarantee she'll get the visa.
2. The VISA packet has to be mailed out somewhere in Guangzhou - and it's not always the 2 to 3 day processing window that GUZ mentions.
3. US Holidays and China Holidays delay visa issuance.
Some folk will buy at R/T ticket for themselves, with a one way ticket, with a 'jump date' out of China within 5 days of interview day. IMO, this is the worst bet you can make. Great on Money, sure, but is highest risk.
Another option is a R/T ticket for you, with an open-ended return date. Is more money, of course, but helps to match up putting you and HER on the plane going out. A cheaper option would be to get a ticket that allows for ONE 'change of return date' - that's usually 100 to 300 bucks extra at time of change, and make that match up with her one-way ticket.
You might want to look at
http://english.ctrip.com, and have your lass look at www.ctrip.com - and get some idea of the ROUTINGS that are available.
Sure, there are ticket agents in the Tianye Building - some of them use the cheapest prices they can, some try for 'all the market will bear' - but - does she have a travel agent friend in her home town? It makes more sense to me, to inquire through that friend, instead.
GOOD LUCK !