I see you might be using the TM graphite L15 irons (3 spin and 4.5 meter)
I'd start off cheap and try to match the SPIN with what seems to work for your game.
Then, since those irons seem to have a slow meter already, I'd check a good ball for METER speed compatibility.
I can't speak for you, but I would check these, and test a few during some rounds.
Srixon Z-STAR Balls (L11+) spin 2.5 meter 2 -180 cred
If these aren't 'sticking' or if the meter is still a little quick I'd try:
Callaway Vapor (L37+) yellow spin 3.5 meter 2.5 -275 cred
(the yellow is good for visibility which is important esp. to a newer player)
If those don't cut it, I'd start testing out ball like the Cally 33 or 34, if you want a more expensive ball w/ a lot more distance I'd start testing out the Nike 61.
But take it all with a grain of salt, you might prefer different ball factors. I had to test out over a half a dozen ball types till I found out what works w/ my clubs and game style.