It sounds like what you need is an advertising agency, and ideally one that specializes (or at least has experience) in your niche. My company (Inedo Media) is just that, but our focus is different than what you need: we help software companies engage and sell their products to software developers.
An advertising agency's scope goes a lot further than simply placing ads ("media buying"). They are your outside point of view and should work hand-in-hand with you to do market research, strategy, messaging/positioning, creatives, and placement... whether that's for social media, direct mail, banner advertising, or anything else. As we put it... it's your job to build and sell a quality product; it's your agency's job to have your product stand from the competition and deliver qualified leads to you.
A quick google search for "b2b technology advertising agency" will turn up plenty of results (and some folks might even give you some recommendations), but what's critical is to learn how to evaluate an agency. But to do that, first consider how an agency will work with you.
Budget. What will you be investing in scaling things up? $1K/mo? $10K/mo? $50K/mo? Invest is the key word here, because this is not a purchase. It doesn't "cost" anything. It simply has a return. The question will be, will this agency deliver a better return than I could?
Goals. What specifically do you want to see happen? 20% increase in sales? Your budget - and the full disclosure of relevant information - will let the agency tell you if your goals are reasonable with your budget.
Commitment. This is where you sign on the dotted line. If you expect (or get) anything free beyond this, remember that you get what you pay for.
Research. What do things look like now? What is your current sales process? What is the best way to accomplish these marketing goals? What problems are these targets facing?
Messaging. Based on research, how do we communicate to our targets? What will help us stand out?
Creatives. Everything from websites to mailers to newsetters to print and banner ads. Writing, design, etc.
Placement. How do we deliver this message? Social media? Websites? Magazines?
Assessment. How can we evaluate the marketing mid-stream and after-the-fact to continually improve and accelerate performance?
Though some agencies will have a different language and a different number of steps, the process is near universal. If there is no process (i.e., they simply follow your direction), then don't even bother. The key things to look for are:
- exlusivity - may seem obvious, but they should not be working or work with a direct competitor
- people and personality - you are hiring an agency, and you will need to work with them hand-in-hand; ideally, you should get along with them
- experience and expertise - especially in your niche
- creative - they need to make you stand out; has their past work demonstrated that they did that?