Hi Purvi. There are pet-shops that do run puppymills. But there are few who are professional and exhibit good ethics. I know few in this city. I'd not mind if I mate my Labrador from stud service offered by a pet-shop as long as I observe the dogs are kept in a humane condition and are given due vetinarian assistance. You can also check with petshops in Gujarat if there're in touch with any chihuahua breeders. I'm sure they will be. There are breeders who supply dogs across India.
Also, I don't think you are an ignorant dogowner. Raising an exotic breed like Chihuahua does require a lot of expertise and it's not everone's cup of tea. So, I'd first say- Hats off to you.
Secondly, could you check with your vet if you could get him neutered?? My knowlege says neutering is a good to go for your dog. You have two advantags in your favour - 1) he's not been mated yet. 2) He's two year old so he's gain all physical growth that the breed requires. Both these two factors makes neutering very conducive for your dog. If you think, he's displaying sexual behaviour which is beyond your tolerance, I'd encourage you to go for neutering. I'm signing off with a good article about neutering written by Caesar Miller- http://www.cesarsway.com/tips/ basics/spay-and-neuter-myths.
If required any assitance then let me know, am available on facebook-http://www.facebook.c om/?ref=home#