Hello
It appears this button is been styled by your Real Estate extensions CSS. Try locating the following in your extensions realestatemanager.css (../components/com_realestatemanager/includes/realestatemanager.css)...
.house_button a,
.admin_table_47 .blank a,
.realestate_search_button,
input[type="submit"],
input[type="button"] {
color: #fff!important;
text-shadow: 0 -1px 0 rgba(0,0,0,0.25);
background: #006dcc!important;
background-image: -moz-linear-gradient(top,#08c,#0044cc)!important;
background-image: -webkit-gradient(linear,0 0,0 100%,from(#08c),to(#0044cc))!important;
background-image: -webkit-linear-gradient(top,#08c,#0044cc)!important;
background-image: -o-linear-gradient(top,#08c,#0044cc)!important;
background-image: linear-gradient(to bottom,#08c,#0044cc)!important;
background-repeat: repeat-x!important;
filter: progid
XImageTransform.Microsoft.gradient(startColorstr='#ff0088cc', endColorstr='#ff0043cc', GradientType=0)!important;
border-color: #0044cc #0044cc #002a80!important;
border-color: rgba(0,0,0,0.1) rgba(0,0,0,0.1) rgba(0,0,0,0.25)!important;
*background-color: #0044cc!important;
filter: progid
XImageTransform.Microsoft.gradient(enabled = false);
-webkit-border-radius: 4px;
-moz-border-radius: 4px;
border-radius: 4px;
-webkit-box-shadow: inset 0 1px 0 rgba(255,255,255,.2), 0 1px 2px rgba(0,0,0,.05) !important;
-moz-box-shadow: inset 0 1px 0 rgba(255,255,255,.2), 0 1px 2px rgba(0,0,0,.05) !important;
box-shadow: inset 0 1px 0 rgba(255,255,255,.2), 0 1px 2px rgba(0,0,0,.05) !important;
border: 1px solid !important;
cursor: pointer !important;
font-family: arial !important;
font-size: 13px;
font-weight: normal !important;
letter-spacing: 1px;
padding: 7px 14px !important;
text-align: center;
text-decoration: none;
white-space: nowrap;
}
And remove the following within...
background: #006dcc!important;
background-image: -moz-linear-gradient(top,#08c,#0044cc)!important;
background-image: -webkit-gradient(linear,0 0,0 100%,from(#08c),to(#0044cc))!important;
background-image: -webkit-linear-gradient(top,#08c,#0044cc)!important;
background-image: -o-linear-gradient(top,#08c,#0044cc)!important;
background-image: linear-gradient(to bottom,#08c,#0044cc)!important;
background-repeat: repeat-x!important;
Ciarán