Hi Sheila,
In order to get rid of the “Use New Venue” & “Use New Organizer” you’d have to modify core files and this is not recommended because you’ll lose your changes on the next update. Also, this drop down is used not only for the front end form but also for the backend form, so if you remove that option, it’s going to be removed in the backend too. You’d need to hack things more to get it to be only on the frond end. Your best bet is probably to hire someone because this is getting into things we can’t help with.
– Jonah