The company, which received £2.95m in EIS funding last year, has since secured a further £1m through Asset Match and is in the process of raising £1.5m through a Seedrs crowdfunding campaign.
Chief executive Simon Lewis told BigHospitality he was confident the target would be met, allowing the Good Old Boy brewer to move forward with its expansion plans.
"We're over 80 per cent and we have until the end of the month. I'm expecting a few more investors to get us to the final target by the end of the month," he said.
"David has raised a lot of money through EIS, but we always knew we'd like to do some crowdfunding. It's not just about getting the money, it's about getting a whole new load of 'fans'. We've got a great community already and this is a way of letting them buy into us and extend our reach."
Lewis, who joined in February 2015 to help steer the company's growth, said it was in talks with the landlord of its Yattendon site to relocate the brewery to that of a neighbouring dairy, which closed last year.
The move, to a larger site, would enable the brewer to increase capacity and introduce a packaging line, which Lewis said would allow them to sell more of its bottled beers to restaurants and pubs.
"We're bursting at the scenes in terms of what space we currently have. Within the year we’ll be maxed out on the current site, so we have to move," he said. "The estate is keen to keep us on the site. This old dairy is perfect, it has drainage, electricity and all the things a brewery needs. As it’s so large it also gives us all the space we’ll need."
"A packaging line will cope with our requirements and add in a contract packaging offer from us as well. There are small breweries which have to fight to get space to get beer into bottle so we can expect to receive enquiries from them. It's all part of our plan to reach more restaurants and hotels serving bottled beers and improve beer's presence on the menus of more places."
West Berkshire Brewery, founded by chairman Bruce and Helen Maggs in 1995, is also planning to open its first pub with the funding. Lewis said he was 'searching all the time' to find Bruce's desired 'stonking great boozer in the middle of town' but competition was fierce.
"We'd love the opportunity to showcase what we do in a pub," he said. "It would start with a beer focus, we're not looking to open a Michelin-starred venue, rather one serving good beer and food."
Lewis said the pub's location could be anywhere in 'the extremes' of its delivery locations, notably London or Bristol, but that it's closest town, Reading was also a possibility 'if a great site came up'.
He said the company would consider expansion once the first was established.
"We'd start with one and if we could do a good job there’s no reason why we wouldn’t open more," he said.