Yeh, pet stores like to sell what they carry, whether or not its good for them. Pet stores also don't care for hedgehogs long term. Often times they base their information on outdated sources. I have had many an argument with pet stores & even a couple of veterinarians on recommendations as they were using sources that are well known to cause harm. I have almost 30 years experience caring for these guys, and most of them have been rescues vs their books...
Sadly, many make it sound like hedgehog care is easy. It is not. They have many requirements in order to stay healthy. I have taken in too many from owners who were under that assumption and realized hedgehogs were not the right pet for them. Now don't get defensive, but as a Rescuer I have to say it.... Should you not be able to provide an appropriate enclosure and food, you may want to reconsider having her and helping her find someone who can.
Now with that said lets try to get back to helping...
Minor foot wounds tend to heal quickly, but Silent Spinners are well known for hurting hedgehogs, you can find a few images of wheels that are covered in blood on here. There are two other wheels that are OK that you may be able to find in the pet store, or your parents could purchase online. The Kaytee Comfort wheel is safer, but still not a great option. There was also a new wheel that was posted on here recently. I have no experience with it, but it looks like a better option:
Noisy Comfort Wheel Alternative!
If you need help convincing them that her wheel is bad, talk to them about her foot injury, and maybe hunt down one of those photos of a bloody wheel and ask if they can at least improve her wheel. Hedgehogs must have wheels and exercise. Veterinary care, if she was to really get hurt, is costly. The cost is $65 for an exam here, and anything extra (meds, sleepy gas, etc) will quickly double and triple that number.
Does your aquarium the type that has the doors that open? Get a ruler and measure it, but I think a common dimension is probably like 36" x 18", which is about 4.5 square ft. Are you allowed to take a picture of it to post it? Maybe we can help figure out how to make it better for her.
Sorry for the novel...