How to gain back my lung capacity after stopping to smoke?

I'm an athlete, more precisely a sprinter and I've been smoking cigarettes for a month now.
I feel really bad about it, mostly because I'm under age and want to be a professional runner when older. Since I'm not yet addicted I feel like it's the right time to stop. Today, I've smoked my last cigarette and sworn to myself that it will stay the last one.

Now I just wonder how much would it take for me to gain my lung capacity back to normal and how
much would it take to get my lungs clear from all the carbon monoxide and stuff?
I'm curious how much time would it take to achieve that when the doctor looks at my lungs he won't actually be able to tell that I was a smoker? Again keep in mind that I've been doing it for
a month only and I didn't smoke every day, I smoked like only 2-3 cigarettes a WEEK except for special occasions like birthdays, but the maximum number of cigarettes I've smoked in a day is 4..

Please don't write pointless stuff like "Oh, you shouldn't have started smoking in the first place.." because I fully understand it and comments like that won't help me now that I've already done it..

Please help, I'll highly appreciate it..
Thanks in advance :)

[hava]

To clean your lungs and boost the lung capacity follow these techniques. After a few weeks, you will not feel the need to smoke.The pranayam will keep you healthy and boost your athletics, so do it for life.
** Your feedback is very important, so other people in similar situation can benefit.
Kapalbhati pranayam -
Build up your timing gradually.If you feel tired or dizzy, stop and resume after one minute.
-(Do it before eating) Push air forcefully out through the nose about once per second. Stomach will itself go in(contract in). The breathing in(through the nose) will happen automatically. Establish a rhythm and do for 20 to 30 minutes twice a day. Children under 15 years – do 5 to 10 minutes twice a day.
Not for pregnant women. Seriously ill people do it gently.

Bhastrika pranayam - Take a long deep breath into the lungs(chest not tummy) via the nose and then completely breathe out through the nose. Place your fists, with the thumb pointing up, on the the legs, above the the knee, and do bhastrika for two minutes.Repeat this  a) with the fists upside down, so that the thumb is pointing down, and resting on the legs, b) with the thumb pointing inwards  c) with the thumb pointing outwards. This will help very much as the lungs open up in different ways.
Repeat this 2 to 5 times during the day.
January 11 ,2011

[hava]

To clean your lungs and boost the lung capacity follow these techniques. After a few weeks, you will not feel the need to smoke.The pranayam will keep you healthy and boost your athletics, so do it for life.
** Your feedback is very important, so other people in similar situation can benefit.
Kapalbhati pranayam -
Build up your timing gradually.If you feel tired or dizzy, stop and resume after one minute.
-(Do it before eating) Push air forcefully out through the nose about once per second. Stomach will itself go in(contract in). The breathing in(through the nose) will happen automatically. Establish a rhythm and do for 20 to 30 minutes twice a day. Children under 15 years – do 5 to 10 minutes twice a day.
Not for pregnant women. Seriously ill people do it gently.

Bhastrika pranayam - Take a long deep breath into the lungs(chest not tummy) via the nose and then completely breathe out through the nose. Place your fists, with the thumb pointing up, on the the legs, above the the knee, and do bhastrika for two minutes.Repeat this  a) with the fists upside down, so that the thumb is pointing down, and resting on the legs, b) with the thumb pointing inwards  c) with the thumb pointing outwards. This will help very much as the lungs open up in different ways.
Repeat this 2 to 5 times during the day.
January 11 ,2011

[Paderla Anitha, DNB]

Hello and hope you are doing well.

I think the best thing you did is to quit smoking. At your age to have good will power is very unique. Kudoos! To you for that and it really shows you to be a strong person. Everybody goes through these phases in life. Since you have been smoking for a short term, it is unlikely to cause any lasting damages to the lungs.  But, lung function tests could further help in evaluation and breathing exercises may help.

Hope this helped and do keep us posted.