Depending on what you or we can do with your website, you may be able to make do with what you have. Here are some things to consider:
First, what is a landing page? When you run a campaign in search marketing, email marketing or direct mail, you want to link to a page that pertains specifically to the offer, product, event or other subject of that campaign. In the case of search marketing, what you pay for a click is partly influenced by relevance of the destination to the ad, and conversely.
Furthermore, high relevance increases the probability your campaign audience follows through on your desired response. A landing page presents information concisely and leads to a specific call-to-action.
A landing page is focused. You might direct a brand awareness campaign to your website's home page but the more specific the campaign, the more specific the destination page should be. If a visitor is interested in a mug you featured in your email campaign, don't link to your home page and make the visitor search for the mug. Go directly to the mug and focus on the click to add to an order. Minimize distractions so the visitor doesn't click elsewhere and eventually wander away. If you're trying to get someone to register for an event, give the who, what, where and when of the event (and why he or she would want to attend), and include the registration form on the page—or at least a first step thereof.
Focus also helps in tracking performance, while allowing for variability elsewhere. Multi-channel campaigns can use copies of the same landing page, one for each source. They can be personalized or segmented for visitors, based on the data you use to launch the campaign. They can include conversion funnels and other indicators of campaign effectiveness. And they can be A/B-tested to tune the message and presentation.