How can I grow my website faster than I'm doing now?

Hey guys, I recently joined the community, I hope it's ok to ask for some personalized growth advice here.

I have a website called jobdirecto.com, its a job board where Hispanic immigrants in NYC can find simple jobs, such as cooking, cleaning, construction, painting, etc. We are also trying to expand to new cities/states such as New Jersey and the metroplex area in Texas.

I live in Germany, so all the growth has been by exclusively by online channels. I was quite poor before the site started making money, so I never spent on advertisement, although now I could put some resources here if it's worth it.

There are basically 2 growth channels I have been using so far: Facebook and Emailing.

The Facebook strategy has been the most effective but also the most time-consuming so far. It consists in sharing screenshots and url of the site in relevant posts of big Facebook groups where Hispanic immigrants gather to find jobs. This fuels both the offer and the demand on the site (people creating job ads and people looking for jobs). I do this every day for about 2 hours. It's not very difficult but it takes work.

The emailing strategy consists in scraping emails from the businesses that need staff and emailing them about jobdirecto. I do this every 3 days using Mailchimp and a scraping bot I built myself. This consumes little time and it only boosts the offer side (businesses creating job ads).

Problems:
1.- Growth in NYC is stagnated and current strategies just keep it afloat.
2.- Growth in new cities/states is rather slow, as I don't own facebook groups in these new cities.
3.- Promoting the group in Facebook groups takes many hours a day and I frequently get my Facebook accounts blocked by group admins, which makes it all more difficult.

Could you give me some ideas, maybe from your personal experience, on how I could increase growth speed in new cities? And how I could increase the growth capacity in NYC?