Here's a problem that's not the easiest to solve: you currently have short or medium length hair but you want to have long, luscious locks and you want them NOW. It's always the way.
You have two options: 1) Spend some money, find a decent stylist, and have extensions added to your hair or 2) Be patient and let your hair grow.
I've never had extensions and I don't think I ever would. There's something weird about it, and they always look so...well...fake. When I think of blonde chicks with extensions, I immediately think about Britney Spears and her lifeless, mop like hair a few months back. Not a good look.
Therefore, I'd just wait for my hair to grow. I always heard that in order to get your hair to grow, you should cut it. I think the theory behind this is that damaged ends don't allow hair to grow well, so cutting away the damage will stimulate growth. It sounds good and yet a bit counter intuitive all at the same time! According to the hair experts, the best thing to do when at an in-between stage is to cut for shape only....without losing a lot of length.
When growing your hair out, you'll probably notice that the ends of your hair are dry and split easily. Since you don't want damaged hair and you don't want to cut your hair, the best thing to do is condition, condition, condition. To avoid split ends, keep your hair moisturized by using a gentle shampoo. In my experience, shampoos you buy in a salon are more gentle than the ones you buy at Target. Of course, they cost more, but you'll have to decide how much you're willing to spend for long, healthy hair. After a gentle shampooing, condition all over, paying particular care to your ends. You may want to consider a weekly deep treatment if your hair is very dry, damaged, or colored.
As your hair grows out to the desired length, you'll no doubt have to deal with awkward in-between lengths. When this happens, use hair bands to keep everything away from your face or try to pull or clip back just the top portion. This will give the rest of your hair movement and won't look so....shall we say...unpolished.
Once you get your long hair, take care of it. Be especially careful if you use a backpack or fling your purse over your shoulder. Trapping your hair under the straps of such things can cause a great deal of breakage...and this type of damage leads to frizz.
There are pros and cons with every hair length out there. But going from short to long takes patience and some care. Once you get the hair you want, though, you'll be glad you invested the time to get your new look!