Monetizing an old and large Joomla directory website

Hello Everyone,

Have been a member of the Warrior forum for quite some time - Always lurking! I've learnt quite a bit from this forum over the years, very grateful it exists.

I have somewhat of a dilemma at the moment and I am hoping I can get some help.

I took over a large directory website built on Joomla and Mosets in 2010. This site lists bars and nightclubs from all over the world. It allows users (who need accounts) to submit places (name, address, phone number, description, photos etc - google map is generated on the page automatically from the address field(s)) and users to rate and review said places.

The site has been in operation since 2002/2003 and the original owners didn't monetize the site at all. When I took it on, I signed up as a publisher with an content relevant banner ad provider who send targeted banner ads to my site and when they are not running (no campaigns are being pushed to the banner spaces on my site) Google Adsense takes their place.

I am making approx $25-30/month from the banner ad provider and approx $50/month for a total approximate $80.00 a month from these banner advertisements.

Analytics was disabled on the site for some time but I re-added it on the 23rd April and since then there have been 11.2k unique visitors (14.5k visits) to the site, 70k pageviews with an average of 3.5 minutes spent on the site. So this gives some indication of traffic. There are approx 5k members on the site with approx 4-5 signing up each day.

The majority of traffic comes from mainland Europe where most of the listings are from, though there is plenty of traffic from all over the world.

I do not market the site. All this traffic is organic, I am ranked very well on Google and backlinks are very good (helped by how old the site is). We get constant attention in the form of blog posts linking to us/places in the directory. Our Facebook and Twitter presence is OK (4.5k fans on Facebook, few hundreds on Twitter).

What I am trying to do is get the site to make more money (easy, huh?! ). The amount I am making at the moment doesn't cover the server bills (there are other sites hosted on the same server) and most definitely doesn't cover the amount of time I pour into the site.

I don't want to monetize the directory at the moment (such as providing "featured" listings for a price, paid listings or anything like this). I am just looking for methods to make some more cash in a not-too-invasive fashion that doesn't cheapen the site and experience for the user.

Please let me know if I can provide any further information.

Thanks,