First of all increasing your budget will only make sense when you are reaching your daily budget sometimes now and it is limiting your number of impressions and clicks. If you are not reaching your daily budget at the moment, but you'd like to increase your impressions and clicks then you should look into new potential keywords that can be added to the campaign (or use other targeting methods for display campaigns).
Since your goal is to generate leads with your campaign it is important that you start tracking how many leads your campaign generates and at what cost. You can use a conversion script from AdWords to track the number of form submissions.
I think it is important to get insight in the performance of your campaign at the moment, before you decide whether to increase your spend or not.