| Lara,
Step one for you is what sounds like a positive change in tone quality. The price of admission is, however, using muscles in a different way than you're used to and that means a temporary loss of range. If you have the courage to stick it out you'll gain later as the new muscles build. No, I don't know how long it'll take but I do know that you should see upward progress from week to week. It'll take consistent practice at staying consistent. Focus on a clear sound throughout your present register, challenge yourself a little each day to ascend but don't abuse your face. Hear each note clearly before you play and hear it as a rich, full sound. Find time at the start of each day for chromatic scales. The first few in the Arban book are perfect for you right now as they are gradual studies meant to expand your sound and range. Also, play the songs from the Art of Phrasing in Arban's. They are in a perfect range to challenge you right now.
Good luck and stay in touch,
ML |