Here are some more thoughts on upgrading.
If you want to upgrade your driver now and have the credits, the L55 that Sam mentioned is the one to get. That's a great driver, and I'm sure it would relieve the frustration. You don't get moved to longer tees until you reach Master (needs an average of 67 which factored into my advice to upgrade irons first).
Upgrading your irons or wedges would probably improve your scores more than upgrading your driver would.
Uprgrading to the L59 irons gets you an upgrade of 8 clubs for around 2500 credits (that's a bargain). High trajectory and more spin matters as you climb the tiers and greens get faster. Don't buy any irons that aren't high trajectory. The L59 3-iron is longer than the Starter hybrid and even a little longer than the Starter 3-wood, so the irons upgrade may even help with your distance frustration.
If you decide to upgrade your driver first, when to upgrade irons may depend on how fast you accumulate credits and how fast you progress through levels. If you're close to L85 by the time you have have enough credits for irons, I'd say wait for the L85 irons instead of getting the L59.
One other thing to consider is that upgrading to good irons is going to increase the gap between the pitching wedge of the iron set and your other wedges. The gap between the 115 yard PW of the L59 irons and the 70 yard Starter wedge is pretty big, so factor in credits to purchase a wedge to fill in that gap if you decide to upgrade irons. High spin wedges will make a big difference with your scores.