how realistic is 45K?

I agree that goals need to be 1. measurable 2. achievable 3. meaningful 4. incremental 5. time realistic

How will you recognize success?
Is it realistic?
How will attaining them positively affect you?
What steps and plan do you have to reach that goal?
What is your time schedule

When do you wish to attain the savings of 45K? Taking into account your current budget, what then is the minimum amount you need to save each month and what is the minimum amount you need to make each month to achieve that goal. How important and necessary is it to have that $17K car?

I suggest talking to someone at your bank. They can help you set a realistic and achievable goal for you.