This girl likes YOU. It may be very well that she's just not comfortable talking on the phone with you yet, and is probably shy, happens alot now a days with texting being so popular. She is looking for a good time, and is probably why she wanted you to come out that night. Don't let this sit around to long because it very possible that she will lose interest. Just text her saying you want to head out and TELL her to come along, don't ask her.
Personally, I talk to other girls and hit on other girls for now, because by the fact that she doesn't want to talk on the phone, means she wants to move at her own pace, don't slow down for her.
You have her interest, enjoy it while it last
Salam Alakoom