There are many themes which have a separate support forum. For example, if you read the Description on the theme’s front page, down towards the bottom you’ll see that the main support forum is here. Sometimes the problem isn’t with the theme, but with the plugin, so you have to decide which support forum you’re going to post on, the theme’s or the plugin’s.
For your particular problem, don’t edit the theme files directly, but use a CSS plugin like JetPack or Custom CSS Manager.
Then create a new rule for the hovered button by copying all of the properties for the non-hover rule and using the selector for the hover rule:
.woocommerce a.button:hover {
font-size: 100%;
margin: 0;
line-height: 1em;
cursor: pointer;
position: relative;
font-family: inherit;
text-decoration: none;
overflow: visible;
padding: 6px 10px;
font-weight: bold;
-webkit-border-radius: 2px;
border-radius: 2px;
left: auto;
text-shadow: 0 1px 0 #ffffff;
color: #5e5e5e;
text-shadow: 0 1px 0 rgba(255,255,255,0.8);
border: 1px solid #c7c0c7;
background: #f7f6f7;
background: -webkit-gradient(linear,left top,left bottom,from(#f7f6f7),to(#dfdbdf));
background: -webkit-linear-gradient(#f7f6f7,#dfdbdf);
background: -moz-linear-gradient(center top,#f7f6f7 0%,#dfdbdf 100%);
background: -moz-gradient(center top,#f7f6f7 0%,#dfdbdf 100%);
white-space: nowrap;
display: inline-block;
-webkit-box-shadow: inset 0 -1px 0 rgba(0,0,0,0.075),
inset 0 1px 0 rgba(255,255,255,0.3),
0 1px 2px rgba(0,0,0,0.1);
-moz-box-shadow: inset 0 -1px 0 rgba(0,0,0,0.075),
inset 0 1px 0 rgba(255,255,255,0.3),
0 1px 2px rgba(0,0,0,0.1);
box-shadow: inset 0 -1px 0 rgba(0,0,0,0.075),
inset 0 1px 0 rgba(255,255,255,0.3),
0 1px 2px rgba(0,0,0,0.1);
}
That should give you a good base from which to start.