It depends upon the terms of your friend's policy if the tow will be covered by her insurance coverage or not. Since she was hit by another car she may be able to put the claim for the damage to her car as well as the tow charge through the at-fault party's liability insurance.

Normally for a tow to be covered by your own auto insurance you would need to add this to your coverage. For example there is a tow and labor add on that with this endorsement, which is added to the physical damage coverage, the motorist is provided with reimbursement up to a specified limit to tow your vehicle or pay for on-site labor costs.