Other members have given you good reply. Considering, that you have already bought a good car Shampoo and have a limited budget. You should probably get a good wax. Turtle hard shell wax is all natural and in our circumstances would only provide protection for a maximum of two week's. You should definitely go with synthetic waxes to have long lasting protection.
Remember, the shine you get out of your car is based on how you prepare your car before waxing. Simple waxing is unlikely to yield magic in terms of shine. So I think you should get a good synthetic wax that last's at least a few month. ( I would recommend Meguiar Nxt paste wax + Meguiar show car glaze 7) Both these products can give amazing results. And with extra elbow effort, you can remove significant oxidation off your car paint with Meguiar #7 without using any abrasive product. And it cost's just 1000rs a bottle.
I recommend you to read this article.
The Secret to Removing Oxidation and Restoring a Show Car Finish to Antique Single Stage Paints - Auto Geek Online Auto Detailing Forum
Although meant for single stage paint, it still works well and is perfectly safe for all type's of paint.
