Smile designing includes all the procedures required to produce the perfect smile. Since your lower teeth are out of archive, I don't think smile designing will make any improvement. It is best to go for orthodontic treatment ("braces").
As far as the price goes... Orthodontic treatment will cost you around 25k to 35k (depending on your dentist). And smile designing cost will depend upon the procedures required for you. For example, for filling in the gaps of your teeth, it will cost around 4k to 5k. If caps or veneers are required, it will cost according to the material (ranging from 2k to 15kfor each tooth).
Next Steps
Consult an Orthodontist
Health Tips
Since in your case multiple teeth are involved, it is best for you to go for orthodontic treatment ("braces").