hi!
has this female been bred to a male? that is the only way she will lay fertile eggs. most likely, she is just gravid, but either way, she will need a place to lay her eggs. Unfortunatly, the stress of buying her, moving her into a new cage, location, etc. could cause a lot of stress on her and she could become egg bound. Luckily though, petco has a 15 day guarentee on herps like that and they will pay for vet bills 
(i used to manage a petco) in the event she becomes egg bound rush her to the vet for medical attention ASAP (but make sure you use Petco's vet! or they wont pay).
also, females lay eggs 3 times a year, so you will always have to monitor them for signs of being gravid. use a 5 gallon bucket with a foot of damp sand and coconut fiber mixed. make sure there are lots vines going in and out of the bucket for easy access. sometimes keeping the surface warmed helps draw them there too. you can also place them directly in an (unused) rubbermaid trash can filled 1/3 with the same mixture and make sure they can't get out. a heat lamp clamped to the side will be fine. in fact you can tell the employees at petco this method as well, since all stores have nice quiet back rooms where she could lay.
a 3 foot by 2 food cage is a little on the small side for an adult veiled. they like height! minimum i would say is 48" x 30" or around there. the cost to build your own cage is much more expensive then to buy one. there are lots of sutible cages for chameleons, you just have to know where to look i keep my two Veiled females (Yema and Arcadia) and Veiled male (Kal) in 100 gallon Reptariums which cost 60.95 at Reptile Harbor Store (online company, enter the name into google and you'll see it). these screen cages have their pros and cons, but as far as cost, esembledge, durability, transportation goes, they are a good option, especially for a first time chameleon owner!
there is A LOT of great information here and on google! keep running search engines for pics of enclosures and other information. i've seen the chameleon care sheet petco offers and it bare minimum of what you need to know. also this site has photogalleries and care sheets too. just learn as much as you can before you bring the chameleon home.
and remember to have a good herp vet too. Chameleons should be treated like a dog or cat would incase of emergency, and not like a lot of other "disposable" herps out there that suffer and die. they have strict requirements and care should be taken to learn EVERYTHING about the specie before bringing them home. aquiring chameleons on impulse can only lead to problems. good luck with your decision and let us know how it goes!
rachel
Pictured below is Arcadia
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4.3 African Clawed Frog
3.3 Calfornia Newt
0.1 Leucistic Texas Ratsnake
1.2 Veiled Chameleon
0.1 Albino Cranwells Horned Frog
0.1 Paddle Tail Newt
0.1 Green Iguana
0.5.0 Indonesian Floating Frog
