I help people get clear on the vision and create the technical plan to make it happen. Worked with FOX, AOL, Anthony Robbins Companies, HGTV, FX, Cirque du Soleil
You should look at what you are extending it for, and first, what your current router setup is.
Make sure that your main router is the latest model. Wireless N has the best range at 2.4GHz with 230ft. Routers have two channels usually, 2.4 GHz and 5 GHz. 5 Will be faster, but cannot penetrate solid objects as well as 2.4.
If you're main router is up to snuff, then look at what you are intending it to be extended for. True wireless extension can be hard as there are many factors that can cause interference or confuse your device between basestation signals.
If at all possible, run a CAT 5e/6 cable to the local you need the signal boosted and plug in a "Wireless Access Point". You can snag these at Best Buy for ~$50. The easiest one to setup in my opinion is the "Apple Airport Express" (even if you aren't using Mac's, they still work great)
If you cannot run a cable, get a "Wifi Extender" but beware. Not all work well and they can cause issues. The easiest one I've setup is using an Apple Airport Extreme as my main router and a Apple Airport Express as the extender. They are meant to work together and the setup is a breeze. If you are running Windows machines at home, you will need the download here to configure it: http://support.apple.com/kb/DL1391
The simple answer is: good developers get paid.
You have a few options that each come with different risks.
1. Find a development agency looking for equity projects. There are more out there than you would expect but be prepared to show them all the details. They are going to want to see that you've done ALL your homework.
2. Find a freelancer looking for passion project. This is hard. Really hard. Try places live Reddit to post what you're looking for with as many details as you can share.
3. Create a "simple-er" MVP. Can up just design a mockup and sell that to investors or customers first? Can you find a way to do it without coding?
People will see value in a lot of ideas but the more you can show them that you've put time into the idea and have hard plans for success, the better the likelihood of finding someone for your project.
Hope that helps!