Welcome to the game. If you search the forums for how do I tier up you will find the information on this. As you say the only way is up, and the better you play the more you will probably enjoy the game.
My advice it to just keep playing and practice a lot using your existing equipment. Try to earn free credits and accumulate them until you reach a higher level (mid 30s), then when you do upgrade, the equipment will last for longer before you outgrow it. Make sure you read the FAQ and video tutorials, and search the forums for tips.
When you feel a bit more confident and level up a little, join a Country Club and play with other players. Most players are willing to give you tips and offer advice.
I actually used the starters equipment for a year but with hindsaight, I wish I had upgraded earlier as the game does get much easier (but be aware the meter speed increases from the starters clubs).
Most importantly, enjoy the game.
Alan