You can book for her Maha Services at the airport : an hostess will assist her in all the paper work / visa and she will not have to wait so long, it is a great service...if you have money to spend you can even take the Platinium service where they will wait for her at the exit of the aircraft. To check Maha Services and contact : http://www.dohaairport.com/services_almaha.html?linksr09.

Then you book a luxurious limo to pick her up / the driver will give her a nice letter that you wrote to her to read during the trip to your place. You can have also prepare her favorite drink to be given by the driver.

I find that nice because anyway in the airport you can not really express your love so it is ok to wait 15 more minutes and meet in your place.