Trans troubles

comments inside the quote. some is a repetition of previous posts.
1972 duster with a 318 in it automatic transmission. I know I probably need to take it to a transmission shop but I'd like to try a couple things first if I can to mabye save a couple.
It does not want to shift out of 1st very well; This sounds like a shifter to roostercomb sync problem.
(also it just does not have any get up like I know it should) this sounds like it never got into first and that she is starting in second gear. You would have to have a manual VB to do this. Unless the pressure systems are fubarred perhaps for lack of a functioning KD mechanism..
And/Or, the throttle is not opening the secondaries; figure out why. Could be a simple as a fat floormat under the gas-pedal.

you have to bring the revs up and let off and then get back on it to shift.
This sounds like low-fluid level, but if not and, if in drive and you are talking about a 1-2 shift, then I would try a band adjustment. If that don't cure it then down she comes.
But if in Drive, going for the 2-3 shift, and the fluid level is up, and the shifter is synced to the roostercomb, then the hi-drum is pooched.

and if I go to pass someone while driving I'll get on it and it feels like it slips into neutral or something so I will have to kind of baby it back into a gear. This sounds like low fluid level or a plugged filter
First time owning a car like this let alone working on one but it's fun and i love it but any ideas will be much appreciated

So the common theme I think is low fluid level or plugged filter.
I would drop the pan inspect for burned fluid and plugged filter. If fluid not wretched then;
replace the filter, adjust the bands, refill with fresh fluid, and check/adjust the shifter sync, check/adjust the KD system,
and finally try again.
If still same , she'll have to come down.