you can try for bidvertiser or adsbrite in these 2 you can get related ads only and another most important thing is that in google you can choose your own related also and block all other non related ads it is very simple just go in manage ads and make your changes
You can manage your ads in your adsense account, by the way, if your site is not receiving traffic then sometimes relevant ads will not display. First of all, drive traffic to your website, blog or whatever you have then check your ads. I'm pretty sure, ads will display which is related to your content.
If you want to try another AD network then Adbrite will be the good option.
Google ads are based on content and keywords. If your content is related with web hosting then there is much chances to see relevant ads on your sites but as you mentioned that your site's niche is completely different. So, this is the main reason to showing irrelevant ads. Even there is option to block irrelevant ads.
Google AdSense is truly a top choice in terms of generating income from the net and I wonder if turning to other programs would help you that much because the basic and important matter is still about generating and having web traffic, not the ads types loading on your pages you know. Your site is to get accessed by a lot of people everyday.
The websites which generate more than one thousand dollars each month from their Google ads are usually enjoying top ranks and experiencing tens of thousands of impressions on a monthly basis. Usually it is the matter of time, using SEO methods as well as traffic building solutions to improve CTR and ROI patterns online.