Theme Modification

I’m building a Used Car Aggregator Portal where Multiple Dealers can Offload their Inventory. I’ll be using Wordpress as the CMS. I’ve already shortlisted the theme for the same from ThemeForest. However, I need Custom Modifications on the following aspects of the theme :

  1. Currently, Once a Dealer submits a Listing, He is taken to Paypal for Payment. But, I want to add other Payment Gateways like Skrill and 2CheckOut.

  2. Secondly, where the Phone Numbers are displayed in the Theme, I want a “Call the Dealer” Button. Once a Buyer clicks on that Button, I’ll initiate a Phone Call between the Buyer and the Seller using Twilio. I’ve already shortlisted a Plugin from Codecanyon for the same. I just want to Integrate the Plugin into the theme and Modify the design of the Theme wherever required.

  3. Thirdly, I want to create a New Feature which will be availaible for Only Premium Dealers. Suppose a Car Buyer comes to My Website. As soon as He comes to My website I’ll Flash a PopUp Form where He will be asked “Which Car He wants to buy, What His budget is etc”. The Details that He enters, will be sent through SMS to those Premium Dealers in Real Time.

Now, I’m on a Shoestring Budget. I’ve already spent around 200$ for buying the theme and Plugins. I can do without a Developer, but the Finesse and Seamless Integration that I can get with a Developer, I won’t be able to do that on My own. I’ve had a conversation with Various Developers that Modify Themes on Themeforest, but there Prices are astonishingly high. I’m not questioning their Work Ethics, its just that I can’t Afford them. So, I request You guys to leave an Estimate down below. The Main thing I value is Cost Effectiveness at this Point in Time.