How Do I Keep Talking With My Girlfriend And About What? She Is The Quiet Type And Expects Me To Talk All The Time. The Problem Is That Most Of The Time I'm At A Loss For Words.

Maybe she doesnt expect you to talk and likes to be silent.  However, you could try asking her wheter she has anything to say.  If she does, then listen, and if she doesnt, then say whatever you have to say.  If you have nothing to say either then tell her so, you don't have to converse all the time.  When you would like to talk then tell her abut your favourite things and ask her about hers.  This should help.

You don't need to keep talking. A good relationship is one where you can have plenty of quiet times and feel comfortable in each others company.
You probably feel obliged to talk a lot because your girlfriend is so quiet and that puts a lot of pressure on you. Tell your girlfriend that it's not necessary to talk all the time and tell her you find the pressure to do so is a strain. Perhaps she needs to get herself a few more interests and then she'll have a lot more to talk about.
If you both find some interests that you can share- say going to the theatre that gives you common ground for something that you can talk about together as shared interests do form the basis for conversation.
Do tell her that you can't keep up leading the conversation and ask her to help or the relationship will eventually suffer.

Bring her out somewhere, (how long have you been together, because if you two just started seeing eachother mabe shes a bit shy), bring her out somewhere to try to get to know her and before you start talking, ALWAYS ask what she wants to do and keep building off what she wants and hopefully she will open up a bit or at least talk a bit more.

Yes. Actually she gets entertained by your conversations but its not possible to keep chitchatting all the time over phone. So the best thing is to quit the call whenever you feel the conversation is a bit boring.... But see that she wont get hurt by the reason you give to quit the call. Good luck!

Talk about things you like. I'm like her cause I'm a really shy person.  Talk about a place you want to go to ,something she likes, something you like. Hope this helped. Or ask her a question then answer it try to get a conversation up.